WAEC SSCE - Agricultural Science - 2019

Study and answer this question

The soil horizon that is not supportive of the growth of tree crops is?

Détails de la réponse

The soil horizon that is not supportive of the growth of tree crops is the one that is not suitable for the growth and development of the roots of the trees. This can be due to several reasons, such as being too shallow, too rocky, too dry, or having poor drainage. In general, tree crops need a deep and well-drained soil to grow strong and healthy roots. A soil that is shallow or has poor drainage can lead to water-logged roots, which can cause the tree to become stunted or even die. Similarly, soil that is too rocky or dry may not have enough nutrients and moisture for the roots to grow, leading to poor tree growth. Therefore, the soil horizon that is not supportive of the growth of tree crops is the one that does not provide the right conditions for the roots to grow and develop.

The vector of leaf curl disease of cotton is?

Détails de la réponse

The vector of leaf curl disease of cotton is the whitefly. A vector is a type of insect that can spread a disease from one plant to another. In the case of leaf curl disease in cotton, the whitefly is the insect that spreads the virus that causes the disease. The whitefly feeds on the sap of the cotton plant, and in doing so, it can spread the virus from an infected plant to a healthy plant. This can lead to the spread of the disease and can cause significant damage to cotton crops.

Which of the following groups of organisms are parasites plants?

Détails de la réponse

A disadvantage of farm mechanization?

Détails de la réponse

One disadvantage of farm mechanization is the displacement of farm workers. As farms become more automated and rely on machines to perform tasks that were once done by hand, there is less need for human labor. This can lead to job loss and unemployment in rural communities that depend on agriculture for their livelihoods. Additionally, the loss of jobs can result in a decline in the quality of life for farmers and their families, as they may be forced to move to urban areas in search of work. This can have negative impacts on the social fabric and economic stability of rural communities.

The least important factor for successful incubation of eggs is?

Détails de la réponse

All of the factors listed are important for successful incubation of eggs, but if we had to choose the least important factor, it would be light. While some species of birds may require specific lighting conditions for successful incubation, many birds do not require any specific lighting at all. Temperature is a crucial factor because eggs need to be kept at a consistent temperature for proper development. Ventilation is also important because it helps to regulate the exchange of oxygen and carbon dioxide, which is necessary for the growth of the embryo inside the egg. Humidity is also crucial because it helps to prevent the egg from drying out and ensures proper moisture levels for the embryo. In summary, while light can be important for some species, it is generally less important than temperature, ventilation, and humidity for successful incubation of eggs.

Sexual propagation of omamental plants involves the use of?

Détails de la réponse

Sexual propagation of ornamental plants involves the use of seeds. Propagation is the process of creating new plants from existing ones. Sexual propagation is one of the two main methods of plant propagation, the other being asexual propagation. Sexual propagation involves the use of seeds to produce new plants. Seeds are the reproductive structures of plants that contain an embryo and a supply of nutrients for the new plant. They are produced when the male and female parts of a flower come together and fertilization occurs. The resulting seeds can be planted in soil, where they will germinate and grow into new plants. Sexual propagation has the advantage of producing genetically diverse offspring, which can lead to new and unique plant varieties. It is also a natural way for plants to propagate themselves in the wild. In summary, sexual propagation of ornamental plants involves the use of seeds, which are the reproductive structures of plants that contain an embryo and a supply of nutrients for the new plant.

Liquid fertilizers and pesticides could be applied through?

Détails de la réponse

A biotic factor affecting agricultural production is?

Détails de la réponse

A biotic factor refers to a living component of an ecosystem that affects other organisms in that ecosystem. In the context of agricultural production, biotic factors can include pests, diseases, and predators. Out of the given options, the biotic factor affecting agricultural production is the predator. Predators such as insects, rodents, and birds can feed on crops and cause significant damage to agricultural production. Farmers have to implement measures such as installing nets or using pesticides to protect their crops from predators. While rainfall, humidity, and temperature are important abiotic factors that can also affect agricultural production, they are not considered biotic factors as they are not living components of the ecosystem.

Which of the following statement about land is not correct?

Détails de la réponse

The statement that "it can be relocated" is not correct. Land is a finite and immovable resource, meaning it cannot be relocated. It is a natural resource that is situated in a specific location and cannot be moved to another location. This is why the location of land is so important in real estate, as it affects the value and use of the land.

Study the graph illustrated above and answer this question correctly 

The graph best_____________

Détails de la réponse

In green manuring, crops are ploughed into the soil just before flowering in order to?

Détails de la réponse

Bone meal is usually included in the diet of livestock to supply?

Détails de la réponse

Bone meal is included in the diet of livestock to supply calcium and phosphorus. Bone meal is made from crushed animal bones that have been finely ground into a powder. This powder is a rich source of calcium and phosphorus, which are both essential minerals for the growth and development of livestock. Calcium is important for strong bones and teeth, while phosphorus is needed for energy metabolism, cell growth, and maintenance of pH balance in the body. By providing these essential nutrients in the diet, bone meal helps to ensure that livestock remain healthy and develop properly.

The main function of the part labelled I is?

Détails de la réponse

If maize seed is sown at a spacing of 100cm x 50cm, determine the expected maize plant population per hectare? 

Détails de la réponse

To determine the expected maize plant population per hectare, we need to convert the given spacing from centimeters to meters, as the hectare is a unit of area in meters. 100cm x 50cm is equivalent to 1m x 0.5m. So the area required per maize plant is 0.5 square meters. Now, to find the number of plants per hectare (which is 10,000 square meters), we divide the total area by the area required per plant: 10,000 sq m / 0.5 sq m per plant = 20,000 plants per hectare. Therefore, the expected maize plant population per hectare is 20,000.

The data for feed consumption and weight gain of our four farm animals labelled P,Q,R and S are shown below.

Use the data to answer this question correctly 

P: 50kg feed consumed and 20kg weight gained.

Q: 90kg feed consumed and 30kg weight gained.

R: 100kg feed consumed and 25kg weight gained.

S: 150kg feed consumed and 30kg weight gained.

The feed conversion efficiency of the poorest weight gainer is?

Détails de la réponse

The diagram above represents the digestive system of a?

Détails de la réponse

A major characteristic of mass teaching method of agricultural extension is that?

Détails de la réponse

Which of the following problems are associated with agricultural marketing in West Africa? I.seasonality of produce II.Transportation of produce III.Access to credit 

Détails de la réponse

Calculate in hectares the area of a rectangular farmland with dimensions 50m by 25m?

Détails de la réponse

The area of a rectangular farmland can be calculated by multiplying its length by its width. In this case, the length of the farmland is 50 meters and the width is 25 meters, so the area is 50m x 25m = 1250 square meters. However, the answer is not in square meters but in hectares, which is a unit of area commonly used to measure land. One hectare is equal to 10,000 square meters. To convert the area from square meters to hectares, we divide the area by 10,000: 1250 square meters / 10,000 = 0.125 hectares. So, the answer is 0.125 hectares, or 0.125ha.

Which of the following statements best describes commercial farming?

Détails de la réponse

Commercial farming is the large scale agricultural production for sale. This means that farmers grow crops or raise animals on a big scale with the intention of selling them to others for a profit. The crops and animals are not just grown for the farmer's own family to consume, but rather to be sold to the market. This type of farming is different from a small family farm, where the focus is on producing food for the family's own consumption, and not necessarily for sale.

The growing of only one crop on a piece of land from year to year is known as?

Détails de la réponse

The growing of only one type of crop on a piece of land repeatedly year after year is called monoculture. This farming practice involves planting the same crop in the same area each year, without changing the crop species or rotating with different crops. Monoculture has several advantages, such as allowing farmers to specialize in one crop and therefore increasing efficiency and yield, but it also has significant disadvantages, including depleting soil nutrients, increasing pest and disease pressure, and reducing biodiversity. Farmers often use chemical fertilizers and pesticides to compensate for these problems, leading to environmental and health concerns.

An advantage of communal land tenure system is that it?

Détails de la réponse

Which of the following hormones is responsible for oestrus in farm animals?

Détails de la réponse

The hormone responsible for oestrus in farm animals is oestrogen. Oestrus is a term used to describe the period of time when a female animal is sexually receptive and fertile. During this time, the levels of oestrogen in the animal's body increase, which triggers a series of physiological changes, including an increase in sexual behavior and a swelling of the reproductive organs. This signals to male animals that the female is ready to mate, and helps to ensure successful fertilization. So, in simple terms, oestrogen is the hormone that causes the female animal to go into heat and become fertile.

The type of rock formed from accumulation of materials transported by water is called?

Détails de la réponse

Sedimentary rock is a type of rock that is formed from the accumulation of materials that have been transported by water, wind, or ice and then deposited. Over time, these deposits build up and get compressed, which eventually turns them into solid rock. Some examples of sedimentary rock include sandstone, limestone, and shale. This type of rock is important because it often contains important information about the environment and climate of the past.

Vegetative growth in fish ponds?

Détails de la réponse

Vegetative growth in fish ponds refers to the growth of plants and algae in the pond water. This type of growth can have several effects on the environment of the pond and the fish living in it. First, the growth of plants and algae can provide shade and shelter for the fish, making their movements easier. The plants and algae also help regulate the acidity of the water, which is important for the health of the fish. Second, the growth of these organisms can increase the turbidity of the pond water, which means that it can become cloudier. This can be beneficial for some species of fish, as it provides them with more hiding places and can reduce the amount of light reaching the bottom of the pond, which can limit the growth of undesirable plants. Finally, the growth of plants and algae in the pond can also moderate the temperature of the water. This is important because fish are cold-blooded animals and their metabolism is affected by changes in water temperature. The plants and algae can help keep the water temperature stable, which is beneficial for the health and growth of the fish.

Which of the following factors of agricultural production is abundant in rural areas?

Détails de la réponse

The data for feed consumption and weight gain of our four farm animals labelled P,Q,R and S are shown below.

Use the data to answer this question correctly 

P: 50kg feed consumed and 20kg weight gained.

Q: 90kg feed consumed and 30kg weight gained.

R: 100kg feed consumed and 25kg weight gained.

S: 150kg feed consumed and 30kg weight gained.

Which of the animals is the most efficient feed converter?

Détails de la réponse

Animal P is the most efficient feed converter among the four animals. This is because it gained 20kg of weight by consuming only 50kg of feed. In contrast, animal Q consumed 90kg of feed to gain 30kg of weight, animal R consumed 100kg of feed to gain 25kg of weight, and animal S consumed 150kg of feed to gain 30kg of weight. Therefore, animal P requires the least amount of feed to gain weight, making it the most efficient feed converter among the four animals.

During the production of palm oil, the oil palm fruits are boiled in order to?

Détails de la réponse

Which of the following statements is not a reason for budding? The resulting plants_______

Détails de la réponse

Which of the  following statement about inbreeding in farm animal is/are false? I.Inbred animals reach market weight early II.Inbred animals have reduced vigour III.Inbreeding increases the occurrences of undesirable traits

Détails de la réponse

Which of the following parasites may be found in the gut of livestock?

Détails de la réponse

Roundworms, also known as nematodes, can be found in the gut of livestock. These parasites live in the intestines of animals and feed on their nutrient-rich digested food. They can cause a range of health problems for the affected livestock, including reduced growth, weight loss, and diarrhea. To prevent the spread of roundworms, it is important to implement good hygiene and management practices on farms, such as regular deworming and keeping pasture areas clean.

A major storage pest of cereals in West Africa is?

Détails de la réponse

The major storage pest of cereals in West Africa is the weevil. Weevils are small, brown beetles that lay their eggs in grain kernels. When the eggs hatch, the larvae feed on the grain, causing damage and reducing its quality. Weevils are particularly problematic in warm and humid environments, which are common in West Africa. They can infest a wide range of grains, including rice, maize, and millet. Infested grains can also attract other pests such as rats and birds, which can further damage the stored grains. Therefore, it is important to take measures to prevent and control weevil infestations in cereal storage in West Africa.

Which of the following breeds of cattle is exotic?

Détails de la réponse

The breed of cattle that is considered "exotic" is the friesian. This breed is considered exotic because it originally comes from the Netherlands and is not commonly found in many countries. It is known for its high milk production and black and white coloring. The other breeds, Sokoto gudali, Ndama, and Muturu are breeds that are native to African countries and are more commonly found in those regions.

The wallow should be provided in the pen of pigs in order to?

Détails de la réponse

A wallow is a muddy area or pool of water that is provided in pig pens. The main purpose of a wallow is to cool down the body temperature of pigs. Pigs do not have sweat glands, so they cannot regulate their body temperature through sweating like humans. They cool themselves by rolling in mud or water, which helps to dissipate heat from their bodies. Therefore, the correct option is that a wallow is provided in the pen of pigs to cool the temperature of pigs. It does not reduce feed intake or increase water intake, nor does it enable pigs to swim.

Determine the equilibrium price of rice.

Détails de la réponse

Determining the equilibrium price of rice depends on the market demand and supply of rice. The equilibrium price is the price at which the quantity of rice demanded by buyers is equal to the quantity of rice supplied by sellers. If the demand for rice is high and the supply is low, the price of rice will increase until buyers are willing to buy less rice or sellers are willing to supply more rice. Conversely, if the supply of rice is high and the demand is low, the price of rice will decrease until buyers are willing to buy more rice or sellers are willing to supply less rice. Without knowing the current market demand and supply of rice, it's impossible to determine the equilibrium price of rice. Therefore, none of the options provided (N1.00, N2.00, N3.00, or N4.00) can be the correct answer. The equilibrium price of rice can only be determined by analyzing the current market conditions of demand and supply.

In animal production, immature spermatozoa are stored in the?

Détails de la réponse

In animal production, immature spermatozoa are stored in the epididymis. The epididymis is a long, coiled tube located at the back of the testes, where spermatozoa mature and are stored. It connects the testes to the vas deferens, which carries sperm to the urethra and out of the body during ejaculation. The urethra is a tube that carries urine and semen out of the body through the penis. It does not play a role in sperm storage. The scrotum is a sac that holds the testes, which produce sperm. It provides the right temperature for sperm production, but it does not store mature sperm. The prostate gland is a small gland located near the bladder, which produces a fluid that nourishes and protects sperm. However, it does not play a role in sperm storage either. Therefore, the correct answer is the epididymis, which is where immature spermatozoa are stored in animal production.

Biological control of insect-pests of crops is carried out through?

Détails de la réponse

In a crop rotation system, it is usually preferred that cassava comes last in the rotation because it?

Détails de la réponse

Which of the following implements is used for primary tillage?

Détails de la réponse

The implement used for primary tillage is a plough. Primary tillage is the first stage of soil cultivation where the soil is broken up and turned over to a significant depth to prepare it for planting. A plough is a farming tool with one or more blades that are used to cut, lift and turn over the soil in preparation for planting. The plough blade is designed to penetrate the soil and cut a furrow, which is then turned over to expose the nutrient-rich soil below the surface. This process helps to loosen and aerate the soil, which makes it easier for plants to take root and grow. On the other hand, cultivators, harrows, and ridgers are all secondary tillage tools that are used after primary tillage to further prepare the soil for planting. Cultivators are used to remove weeds and break up the soil surface to improve water penetration, while harrows are used to level the soil and break up clumps of soil. Ridgers are used to create ridges or furrows in the soil to plant crops. In conclusion, a plough is used for primary tillage, which is the first stage of soil cultivation where the soil is broken up and turned over to prepare it for planting. Other tools like cultivators, harrows, and ridgers are used for secondary tillage to further prepare the soil for planting.

The practice of measuring and mapping out the size, position and boundary of a farmland is called farm?

Détails de la réponse

The practice of measuring and mapping out the size, position and boundary of a farmland is called surveying. This involves using tools and techniques to accurately determine the boundaries of the land, its size and its location on a larger map. Surveying is an important aspect of farming as it helps farmers to know exactly where their land begins and ends, which can be useful in preventing disputes with neighboring farms or in accurately applying fertilizers and other inputs to the crops.

The growth of both trees and arable crops on the same piece of land is?

Détails de la réponse

What is the change in quantity of rice demand when the price increases from N1.00 to N5.00?

Détails de la réponse

Corns, rhizomes and tubers are examples of?

Détails de la réponse

Corns, rhizomes and tubers are examples of underground stems. Stems are the part of the plant that supports leaves, flowers, and fruits. They also transport water, nutrients and sugars from the roots to other parts of the plant. Some plants have stems that grow underground, which are called underground stems. Corns, rhizomes, and tubers are all examples of underground stems. Corns are thickened underground stems that store food for the plant. They are commonly found in grasses like corn, wheat, and barley. Rhizomes are horizontal underground stems that produce roots and shoots at their nodes. They can grow new plants and help the plant spread quickly. Ginger and turmeric are examples of plants that have rhizomes. Tubers are enlarged, fleshy underground stems that store food for the plant. They often have buds, or "eyes," that can sprout new plants. Potatoes are the most well-known example of tubers. In summary, corns, rhizomes, and tubers are all types of underground stems that allow plants to store food and propagate themselves.

Study and answer this question below

A periodic maintenance activity carried out on the illustrated farm machinery is?

Détails de la réponse

Protective functions of forests include the following except

Détails de la réponse

The protective function of forests that is not included in the list is serving as a source of firewood. Forests play a crucial role in protecting the environment by conserving soil, acting as a windbreak, and purifying the air. However, they are not specifically designed to serve as a source of firewood. Instead, they provide a habitat for wildlife, regulate the water cycle, and help mitigate climate change by absorbing carbon dioxide from the atmosphere.

A fresh garden soil sample weighed 25kg. When oven-dried, its weight reduced to 20kg. Calculate the percentage moisture content of the soil sample.

Détails de la réponse

To calculate the percentage moisture content of the soil sample, we need to first find out the weight of the water that was present in the original sample. The weight of water in the original sample can be found by subtracting the weight of the dried sample from the weight of the original sample: Weight of water = Weight of original sample - Weight of dried sample = 25 kg - 20 kg = 5 kg Now, we can use the following formula to calculate the percentage moisture content: Percentage moisture content = (Weight of water / Weight of original sample) x 100% Substituting the values we obtained, we get: Percentage moisture content = (5 kg / 25 kg) x 100% = 20% Therefore, the percentage moisture content of the soil sample is 20%.

Which of the following statements are advantages of mulching? it I.Controls weeds II.Conserves soil moisture. III.Increases soil temperature. IV.Reduces soil pH.

Détails de la réponse

The following statements are advantages of mulching: I. Controls weeds II. Conserves soil moisture Mulching involves covering the soil surface around plants with a layer of organic material such as leaves, grass, straw, or wood chips. The organic material acts as a barrier that blocks sunlight from reaching weed seeds, preventing them from germinating and growing. Therefore, mulching can help control weeds naturally without the use of chemicals. Mulch also helps to conserve soil moisture by reducing evaporation from the soil surface. It helps to retain moisture by slowing down water loss from the soil through evaporation. As a result, plants can access the water they need for growth and development, and water is used more efficiently. However, mulching does not increase soil temperature or reduce soil pH. In fact, mulching can help to moderate soil temperature by keeping the soil cooler in hot weather and warmer in cool weather. Mulching does not have a direct impact on soil pH either. Therefore, the correct answer is: I and II.

Which of the following mineral elements is essential for chlorophyll formation?

Détails de la réponse

Magnesium is essential for chlorophyll formation. Chlorophyll is a green pigment found in plants that plays a crucial role in photosynthesis, the process by which plants make their own food. Magnesium is a central component of chlorophyll molecules, and without it, chlorophyll cannot be produced. This means that plants with a magnesium deficiency will have stunted growth and yellowing leaves, as chlorophyll is necessary for the plant to perform photosynthesis and produce energy.

A planting material used in propagating plaintain is the?

Détails de la réponse

A socio-cultural factor affecting land availability is?

Détails de la réponse

Land availability is affected by various socio-cultural factors, such as religion, social norms, and traditional beliefs. For example, in some cultures, land is considered a sacred resource and cannot be bought or sold. This can limit land availability, particularly in areas where these cultural beliefs are prevalent. Therefore, the correct option is religion, as it is a socio-cultural factor that can affect land availability. Soil type, topography, and mining are environmental and economic factors that can affect land availability, but they are not directly related to socio-cultural factors.

TEST OF PRACTICAL KNOWLEDGE QUESTION

(a) State three uses each of specimens A (RAKE), C (SHOVEL), and D (CUTLASS)

(b) Describe Specimen E (WHEELBARROW).

(C) State three ways of maintaining Specimen E.

Détails de la réponse

(a)

Specimen A (RAKE):

1. Clearing leaves and debris in a garden or lawn.
2. Leveling soil or sand in preparation for planting or laying a surface.
3. Sifting soil or compost to remove rocks or clumps.

Specimen C (SHOVEL):

1. Digging holes for planting trees or posts.
2. Moving soil, sand, or gravel from one place to another.
3. Excavating trenches for plumbing or electrical work.

Specimen D (CUTLASS):

1. Clearing brush and undergrowth in a forest or field.
2. Harvesting crops such as sugar cane or rice.
3. Cutting small trees or branches for firewood.

(b)

Specimen E (WHEELBARROW):

A wheelbarrow is a small, single-wheeled garden cart used for transporting materials such as soil, sand, gravel, or debris. It is typically made of metal or plastic and has two handles at the back for pushing and a tray at the front for holding the material being transported.

(c)

Three ways to maintain a wheelbarrow include:

1. Regular cleaning to remove dirt and debris, which can help prevent rust and other damage.
2. Lubricating the wheel axles to ensure smooth operation and prevent wear and tear.
3. Checking the tire pressure and making sure the wheel is properly inflated, which will help prevent the wheel from going flat and make the wheelbarrow easier to use.

The diagram below illustrates an experimental set-up on soil. Study it and answer the questions that follow.

a) (i) State the aim of the experiment. 

(ii)Name the parts labelled I and II in the diagram.  

b) Describe how the experiment is carried out. 

c) State four properties of sandy soils. 

 d) Describe a test for soil acidity using litmus paper. 

Détails de la réponse

a)  Aim of the experiment

• Separation of soil into its fractions/determination of soil texture by sedimentation  

(ii) Naming of the parts labelled I and II

b)

In the experiment, soil is placed in the funnel (Part I), and water is poured over it. The water passes through the soil and collects in the measuring cylinder (Part II). The volume of water collected in the measuring cylinder is used to determine the water-holding capacity of the soil.

• Place a glass jar on a surface
• Weigh about 70 – 100g of the soil
• Add the weighed soil into an equivalent quantity of water in a glass jar
• Add suitable dispersing agent e,g, NaOH, NaHCO3
• Shake the glass jar vigorously to disperse any soil clods
• Allow the glass jar to settle for an hour
• Observe the result

c)

Four properties of sandy soils are:

1. Low water-holding capacity
2. Low nutrient retention
3. Good drainage
4. High porosity

d)

To test soil acidity using litmus paper, a small amount of soil is mixed with distilled water to form a paste. A red litmus paper is then dipped into the paste. If the litmus paper turns blue, it indicates that the soil is acidic. If the litmus paper remains red, it means the soil is neutral or alkaline. This test is based on the principle that acidic substances turn blue litmus paper red.

(a) A farmer purchased a tractor in the year 2000 for D 12, 000.00. In 2009, the tractor was
sold for D 3,000.00 as it was no longer economical to keep. Calculate the:

(i)  useful life of the tractor;
(ii) salvage value of the tractor;
(iii) total depreciation of the tractor;
(iv) annual depreciation of the tractor.  

(b) Describe the following terms as used in agricultural economics:
(i)  demand schedule;
(ii) supply curve.  

(c) List four agricultural extension agencies in West Africa. 

(d) State four ways through which soils are enriched with nitrogen.

Détails de la réponse

(a) (i) The useful life of the tractor can be calculated as the difference between the year it was purchased and the year it was sold.
Useful life = Year of sale - Year of purchase Useful life = 2009 - 2000 Useful life = 9 years
(ii) The salvage value of the tractor is the amount it was sold for when it was no longer economical to keep.
Salvage value = D3,000.00
(iii) The total depreciation of the tractor can be calculated as the difference between its purchase price and its salvage value.
Total depreciation = Purchase price - Salvage value Total depreciation = D12,000.00 - D3,000.00 Total depreciation = D9,000.00
(iv) The annual depreciation of the tractor can be calculated by dividing the total depreciation by its useful life.
Annual depreciation = Total depreciation / Useful life Annual depreciation = D9,000.00 / 9 Annual depreciation = D1,000.00
Therefore, the annual depreciation of the tractor is D1,000.00.
(b) (i) Demand schedule is a table that shows the various quantities of a product or service that consumers are willing and able to purchase at different prices, over a given time period.
(ii) Supply curve is a graphical representation that shows the quantity of a product or service that producers are willing and able to offer at different prices, over a given time period.
(c) Four agricultural extension agencies in West Africa are: - The West and Central African Council for Agricultural Research and Development (CORAF) - The National Agricultural Extension and Research Liaison Services (NAERLS) in Nigeria - The Department of Agricultural Extension Services (DAES) in Ghana - The Institut National des Recherches Agricoles du Bénin (INRAB) in Benin
(d) Four ways through which soils are enriched with nitrogen are: - Crop rotation: where leguminous crops such as beans and peas are grown and then plowed back into the soil to enrich it with nitrogen. - Green manure: where plants such as clover, alfalfa, or rye are grown and then plowed back into the soil to enrich it with nitrogen. - Animal manure: where livestock manure such as cow or poultry manure is added to the soil to enrich it with nitrogen. - Nitrogen fixing bacteria: where certain bacteria, such as Rhizobia, live in nodules on the roots of leguminous plants and convert atmospheric nitrogen into a form that plants can use.

(a) What is depreciation in agricultural production?                       

(b)  Distinguish between the following pairs of terms as used in agricultural production:
(i)  farm records and farm accounts;
(ii)  credit and subsidy;
(iii) assets and liabilities.                                              

(c)  State five problems of agricultural extension in West Africa.              

(d)  Enumerate five factors that affect the supply of cassava in West Africa

Détails de la réponse

(a) Depreciation in agricultural production refers to the decrease in value of an asset due to wear and tear, obsolescence, or other factors that reduce its usefulness over time. In agriculture, this might refer to things like tractors, machinery, or other equipment that becomes less effective as it is used.

(b)

1. Farm records are a systematic way of keeping track of information about a farm, such as production and expenses. Farm accounts are a more comprehensive way of tracking the financial performance of a farm, including both income and expenses.

2. Credit refers to the loan of money or other resources, usually with the expectation that it will be repaid with interest. Subsidy refers to financial assistance from the government to support a particular industry or activity, such as agriculture.

3. Assets are resources that a farm has and can be used to generate income, such as land, buildings, or equipment. Liabilities are obligations or debts that the farm owes, such as loans or taxes owed.

(c)

Five problems of agricultural extension in West Africa are:

1. Lack of funding and resources, which limits the ability of extension services to reach farmers and provide them with the information and support they need.
2. Limited access to information and technology, which can make it difficult for farmers to adopt new practices and improve their production.
3. Inadequate infrastructure, such as roads, storage facilities, and communication networks, which can limit the ability of extension services to reach farmers in remote areas.
4. Limited capacity and skills of extension workers, which can make it difficult for them to provide farmers with the information and support they need.
5. Lack of coordination and collaboration between different organizations and government agencies, which can result in duplication of effort and a lack of consistency in extension services.

(d)

Five factors that affect the supply of cassava in West Africa are:

1. Climate: Changes in temperature and rainfall patterns can affect the growth and productivity of cassava crops.
2. Soil fertility: Poor soil quality can limit the ability of cassava plants to grow and produce a high yield.
3. Pest and disease management: Outbreaks of pests and diseases can cause significant damage to cassava crops and reduce their yield.
4. Access to markets: The ability of farmers to sell their cassava products is influenced by the availability of markets and the price they can receive for their crops.
5. Availability of inputs: Factors such as the availability of seeds, fertilizer, and labor can affect the ability of farmers to grow and harvest cassava crops.

(a) Using the table below, classify the following crops based on their life cycle.

(b) List four components of a typical soil with their percentage volume.

(c) State three methods of applying inorganic fertilizers to the soil.

Détails de la réponse

(a) Crop classification based on life cycle: Crop | Classification based on life cycle ---|--- Mango | Perennial Rice | Annual Groundnut | Annual Cotton | Annual Pepper | Annual or Perennial (depending on variety) Soya bean | Annual Oil palm | Perennial Yam | Perennial Tomato | Annual Rubber | Perennial Ginger | Perennial Cocoa | Perennial Cowpea | Annual Carrot | Biennial (b) Four components of a typical soil and their percentage volume are: Soil component | Percentage volume ---|--- Mineral particles | 45% Organic matter | 5% Water | 25% Air | 25% (c) Three methods of applying inorganic fertilizers to the soil are: 1. Broadcasting: In this method, the fertilizer is uniformly spread over the soil surface. This can be done by hand or using a machine. Broadcasting is a quick and easy method but can result in uneven distribution of the fertilizer. 2. Banding: In this method, the fertilizer is applied in a concentrated band or row directly where the plant roots are located. This helps to ensure that the fertilizer is available to the plants when they need it. Banding requires more effort than broadcasting, but it can result in better fertilizer use efficiency. 3. Foliar application: In this method, the fertilizer is applied as a spray directly to the leaves of the plants. This is a quick and efficient way to provide nutrients to the plants, especially during periods of rapid growth or when the plants are under stress. However, foliar application is not a substitute for soil fertilization and should be used in combination with other methods.

TEST OF PRACTICAL KNOWLEDGE QUESTION

Take a sample each of specimens F (CLAY SOIL), G (LOAMY SOIL) and H (SANDY SOIL) and rub each between the thumb and forefinger. Put a sample of each of the specimens on your palm and add a little amount of water sufficient to wet it. Mix each sample with water. Attempt producing a roll and then a ring. 

(a) Tabulate your observations from the experiment.

(b) Name two crops that can be grown on specimen H.

(c) (i) Which of specimens F,G, and H is preferred for maize productions?
(ii) Give three reasons for your answers in (c)(i).

(d) State three ways in which specimen l (EARTHWORM) is of economic importance in agriculture.

Détails de la réponse

a) Observation table:

b) Two crops that can be grown on specimen H (sandy soil) are watermelons and peanuts.

c) (i) Specimen F (clay soil) is preferred for maize production.

(ii) Three reasons for the preference of clay soil for maize production are:

1. Clay soil has high water retention capacity, which ensures consistent moisture for the maize plant.
2. Clay soil has high nutrient retention capacity, which means that the maize plant can access nutrients for a longer time, leading to better growth and yield.
3. Clay soil has good soil structure, which allows for good aeration and root penetration, essential for good maize plant growth.

d) Three ways in which earthworms are of economic importance in agriculture are:

1. Soil fertility: Earthworms burrow through soil, aerating it and mixing organic matter with soil particles. This process enhances soil fertility, which leads to better crop growth and yield.
2. Vermicomposting: Earthworms feed on organic waste material and excrete nutrient-rich castings, which can be used as organic fertilizer. This process of vermicomposting reduces waste, produces fertilizer, and saves money that would have been used to purchase chemical fertilizers.
3. Soil structure: Earthworms burrow through soil, creating channels for water and air to flow through. This process enhances soil structure, which allows for better root penetration and nutrient absorption by crops. Good soil structure also reduces soil erosion and improves water infiltration.

a) Explain each of the following terms as used in animal production:
(i)  flushing;
(ii) castration;
(iii) culling. 

(b) Mention two advantages of each of the terms in 5 (a).
(i)   Flushing;
(ii)  Castration;
(iii) Culling. 

(c) Give two uses of each of the following survey equipment:
(i) prismatic compass;
(ii) measuring tape.

(d) Differentiate between the terms floriculture and aquaculture.

Détails de la réponse

(a)
(i) Flushing: In animal production, flushing refers to the practice of increasing the nutrition of breeding animals, typically cows or ewes, prior to mating in order to improve their reproductive performance and increase the number of eggs or embryos produced.
(ii) Castration: In animal production, castration refers to the removal of the testicles of male animals, typically for the purpose of making them easier to manage and reducing aggressive behavior.
(iii) Culling: In animal production, culling refers to the selective removal of animals from a herd or flock for reasons such as poor health, low productivity, or poor genetics.

(b)
(i) Advantages of flushing:
1. Increased reproductive performance and egg or embryo production.
2. Improved fertility and conception rates.
(ii) Advantages of castration:
1. Reduced aggressive behavior and improved animal welfare.
2. Improved meat quality and consistency.
(iii) Advantages of culling:
1. Improved herd or flock productivity and genetics.
2. Improved animal welfare by removing animals that are suffering or unable to contribute to the herd or flock.

(c)
(i) Prismatic compass:
1. Survey work, such as determining property boundaries and elevations.
2. Orienteering and navigation, such as finding one's way through the wilderness.
(ii) Measuring tape:
1. Construction and carpentry, for measuring and cutting materials to the correct size.
2. Tailoring and sewing, for measuring fabric and determining the correct size for clothing.

(d) Floriculture refers to the cultivation of flowers and ornamental plants, while aquaculture refers to the cultivation of aquatic animals and plants, such as fish, crustaceans, and seaweed. The main difference between the two is that floriculture is focused on growing plants for ornamental purposes, while aquaculture is focused on raising aquatic species for food or other purposes.

(a) (i) Name the disease associated with the observed symptoms. 
(ii) List three ways of controlling the disease named in 2(a)(i). 

(b) (i) State three pests of cocoa. 
(ii) State three ways of controlling the pests mentioned in 2(b)(i). 

(c)Enumerate five factors to be considered in siting a crop farm;

(d) Mention three ways of maintaining survey equipment. 

Détails de la réponse

(a)

(i)   Name of the disease

• Black pod disease of cocoa

(ii) Ways of controlling the disease

• Remove and destroy infected pods.
• Weed regularly.
• Prune lower branches and canopy.
• Apply fungicide

(b)

i)Three pests of cocoa are capsids, mealybugs, and mirids.

ii) Three ways of controlling the pests mentioned in 2(b)(i) are:

- Biological control: Introduce natural enemies of the pests such as predators, parasites, or diseases to reduce their population.

- Chemical control: Use pesticides to kill the pests

- Cultural control: Adopt practices such as regular pruning, maintaining good drainage, and maintaining good farm hygiene to prevent pest infestation.

(c)

Five factors to be considered in siting a crop farm are:

1. Soil type and fertility: The soil should be fertile and suitable for the crops to be grown.
2. Climate and weather conditions: The crop farm should be in an area where the climate and weather are favorable for the crops to be grown.
3. Water availability: The farm should be located in an area with adequate water supply for irrigation and other farming activities.
4. Accessibility: The farm should be easily accessible by roads or other means of transportation for easy movement of farm inputs and products.
5. Market proximity: The farm should be located close to the market to reduce transportation costs and improve profitability.

(d)

Three ways of maintaining survey equipment are:

1. Regular cleaning: The equipment should be cleaned after each use to remove dust and debris that may cause damage.
2. Regular calibration: The equipment should be calibrated regularly to ensure that it is accurate and reliable.
3. Proper storage: The equipment should be stored properly in a clean, dry, and secure place to prevent damage or theft.

TEST OF PRACTICAL KNOWLEDGE QUESTION

(a) Using a table, classify specimens J, K, L, M, N and O into the following crops groups: Fruit, Leafy vegetable, Bulb and Root.

(b) List five general cultural practices that are carried out by farmers when growing Specimens J, K, L, M, N and O.

(c) State four ways in which the growing of Specimens J, K, L, M, N and is important to humans.

Détails de la réponse

(a) Specimen classification:

(b) General cultural practices:

• Land preparation: Farmers prepare the land by clearing weeds and other unwanted plants, tilling the soil, and adding organic matter like manure or compost.
• Irrigation: Providing sufficient water is crucial for the growth and development of crops, so farmers may use irrigation systems or rely on rainwater.
• Fertilization: Plants need nutrients to grow, and farmers may add fertilizers to the soil to provide these nutrients.
• Pest and disease control: Farmers may use various methods to control pests and diseases, such as using natural predators or chemical treatments.
• Harvesting: When the crops are mature, farmers harvest them by hand or using machines, depending on the crop and farm size.

(c) Importance of growing specimens:

• Food source: Specimens J, K, L, M, N, and O are all crops that provide food for humans. By growing these crops, farmers help to ensure that people have access to a variety of fresh, healthy foods.
• Economic benefits: Agriculture is an important industry that provides jobs and income for many people, especially in rural areas. Growing crops like these specimens can help support local economies and provide income for farmers.
• Environmental benefits: Growing crops can also have environmental benefits, such as preventing soil erosion, promoting biodiversity, and reducing greenhouse gas emissions.
• Cultural significance: Many of these crops have cultural significance for certain communities or regions, and growing them helps to preserve and celebrate these traditions.

The diagrams below illustrate parasites of farm animals

Study them and answer the questions that follow.

a) Identify the parasites labelled I and II. 

b) Mention three external features of the parasite labelled I. 

c) Name the part of the body of the host where the parasite labelled II is found.

(i) State four adaptive features of the parasite labelled II on its host. 
(ii) List two intermediate hosts of the parasite labelled II. 

d) State three effects of the parasite labelled I on its host.

e) State three effects of the parasite labelled I on its host.

Détails de la réponse

a) The parasite labelled I is a tick, while the parasite labelled II is a liver fluke.

b) Three external features of the tick (parasite I) are its hard, flattened body covered in a tough, chitinous exoskeleton, eight legs, and a mouthpart structure called a hypostome used for anchoring and feeding.

c) The liver fluke (parasite II) is found in the liver of the host animal.

(i) Four adaptive features of the liver fluke on its host are:

- A flat body shape that allows it to move easily through narrow spaces in the liver.

- Hooks and suckers on its body that help it attach to the liver tissue.

- The ability to secrete chemicals that prevent the host's immune system from attacking it.

- The production of eggs that are passed out of the host's body in the feces, allowing the parasite to continue its life cycle.

(ii) Two intermediate hosts of the liver fluke are snails and ants.

d) Three effects of the tick (parasite I) on its host are:

- The transmission of diseases such as Lyme disease and tick-borne fever.

- Irritation and itching at the site of the tick bite.

- Anemia, or a decrease in the number of red blood cells, due to the tick's blood-feeding behavior.

e) Three effects of the liver fluke (parasite II) on its host are:

- Liver damage, including inflammation, scarring, and tissue death.

- Reduced growth and productivity in farm animals due to decreased feed intake and weight gain.

- Increased susceptibility to other diseases due to the weakening of the immune system by the liver fluke's presence. Liver flukes are responsible for significant economic losses in the livestock industry, and can also infect humans who consume contaminated food or water.

(a) (i) Differentiate between intensive system and extensive system of livestock management. 
(ii) State five disadvantages of keeping livestock on free range system. 

(b) State six ways in which ornamental plants are important.

Détails de la réponse

(a)

(i) Intensive system and extensive system of livestock management differ in the level of input and management involved. Intensive system involves high input and management with a small number of livestock kept in a small area while extensive system involves low input and management with a large number of livestock kept in a large area.

(ii) Five disadvantages of keeping livestock on free range system are:

1. Increased risk of disease transmission among animals due to closer contact and exposure to pathogens.
2. Limited control over breeding and genetics of animals.
3. Lack of proper shelter and protection from predators, adverse weather conditions, and theft.
4. Overgrazing and degradation of pastureland, which can lead to soil erosion and reduced productivity.
5. Difficulty in monitoring and managing animal health and welfare.

(b) Six ways in which ornamental plants are important are:

1. Aesthetic value: Ornamental plants are grown for their beauty and add color, texture, and interest to gardens, parks, and public spaces.
2. Environmental benefits: Ornamental plants can help reduce air pollution, noise pollution, and soil erosion, and contribute to carbon sequestration.
3. Economic benefits: The production and trade of ornamental plants contribute to local and national economies through employment and revenue generation.
4. Cultural significance: Ornamental plants have cultural and historical significance in many societies, and are often used in art, literature, and religious practices.
5. Psychological benefits: Exposure to ornamental plants has been linked to improved mental health, reduced stress, and increased feelings of happiness and well-being.
6. Educational value: Ornamental plants provide opportunities for learning about botany, horticulture, and ecology, and can be used for educational purposes in schools and other institutions.

Explanation: Ornamental plants serve many purposes, from beautifying our surroundings to providing environmental, economic, cultural, and psychological benefits. They also have educational value, making them a valuable resource for learning and research.

(a) (i) Define the term drainage.
(ii) State four reasons why waterlogged agricultural land should be drained. 

(b)List six factors affecting nutrient availability in the soil.

(c) Complete the table below on the causative organisms of crop diseases.

Détails de la réponse

(a)

(i) Drainage refers to the process of removing excess water from a land or soil through artificial means such as ditches, pipes, or channels to ensure proper moisture levels for plant growth.

(ii) Four reasons why waterlogged agricultural land should be drained are:

1. To prevent oxygen deprivation in plant roots, which can lead to plant death or stunted growth.
2. To prevent the accumulation of harmful salts in the soil, which can negatively affect plant growth and yield.
3. To prevent soil erosion caused by runoff from waterlogged land.
4. To reduce the incidence of plant diseases caused by water-loving organisms.

(b)

Six factors affecting nutrient availability in the soil are:

1. Soil pH: Nutrient availability is affected by soil pH levels. Some nutrients are only available within certain pH ranges.
2. Soil organic matter: Soil organic matter plays an essential role in nutrient cycling and availability in the soil.
3. Soil texture: Soil texture influences nutrient availability by affecting water-holding capacity and nutrient retention in the soil.
4. Soil temperature: Soil temperature affects nutrient availability by influencing the rate of nutrient release from organic matter and the activity of soil microorganisms.
5. Soil moisture: Soil moisture affects nutrient availability by influencing the solubility and mobility of nutrients in the soil.
6. Soil aeration: Soil aeration affects nutrient availability by influencing the rate of microbial activity and the oxidation of organic matter.

(c)

Completing the table on the causative organisms of crop diseases:

Explanation: - Rice blast is caused by a fungus called Magnaporthe oryzae. - Groundnut rosette is caused by a virus. - Cassava mosaic is caused by a virus. - Root knot of tomato is caused by a nematode, a type of microscopic worm. - Maize rust is caused by a fungus called Puccinia polysora. - Tristeza is caused by a virus.

Study the farm implement illustrated below and answer the questions that follow.

a) Identify the farm implement illustrated. 

(ii)Name the parts labelled I and II III IV in the diagram. 

b) State one function of each of the parts labelled I, II, III and IV.

c) Mention the farm operation for which the illustrated implement is used. 

d) List two farm tools that can perform similar functions as the illustrated implement. 

e) State three ways of maintaining the illustrated implement.

Détails de la réponse

(a) The farm implement illustrated is a disc plough.

(b) The functions of the labelled parts are:

• Part I: Disc blades. They cut and turn over the soil.
• Part II: Hitch. It is used to attach the implement to a tractor or other pulling equipment.
• Part III: Frame. It holds the disc blades and other parts together.
• Part IV: Depth adjustment mechanism. It is used to adjust the depth of the cut made by the disc blades.

(c) The illustrated implement is used for primary tillage operations, such as breaking up and turning over soil in preparation for planting.

(d) Two farm tools that can perform similar functions as the illustrated implement are the mouldboard plough and the chisel plough.

(e) Three ways of maintaining the illustrated implement are:

• Regular cleaning: After use, the implement should be cleaned to remove any soil, debris or plant material that may have accumulated on it. This prevents rust and corrosion and helps to prolong the life of the implement.
• Lubrication: The moving parts of the implement, such as the disc blades and bearings, should be lubricated regularly to reduce friction and prevent wear and tear.
• Storage: The implement should be stored in a dry and secure place to prevent damage from weather, pests or theft. It should also be covered to prevent dust and other contaminants from settling on it.

(a) Complete the table below.            

(b)  List three examples of each of the following factors affecting land availability for  
agriculture:
(i)  physical factors;
(ii) economic factors.   

(c) Enumerate four effects of pollution on agricultural lands and ponds.       

(d) State two ways of minimizing land and pond pollution.             

Détails de la réponse

(a)
Weed | Botanical Name | Method of Dispersal
--- | --- | ---
Goat weed | Ageratum conyzoides | Wind and animals
Siam weed | Chromolaena odorata | Wind and animals
Water leaf | Talinum triangulare | Water and animals

(b)
(i) Physical factors affecting land availability for agriculture include: soil type, climate, and topography. For example, land with poor soil fertility or a steep slope may not be suitable for agriculture.
(ii) Economic factors affecting land availability for agriculture include: land prices, land tenure systems, and market demand for agricultural products. For example, high land prices may make it difficult for small-scale farmers to access land, while strong demand for certain crops may lead to land conversion from other uses.

(c)
Four effects of pollution on agricultural lands and ponds include: reduced soil fertility, loss of biodiversity, contamination of crops and water sources, and reduced fish populations. Pollution can also lead to increased disease incidence in both plants and animals.

(d)
Two ways of minimizing land and pond pollution include: reducing the use of chemical fertilizers and pesticides, and implementing proper waste management practices. For example, farmers can use organic fertilizers and biological pest control methods to reduce chemical pollution, while waste from livestock can be properly managed through composting or other methods to reduce contamination of water sources.

(a) Distinguish between spacing and thinning in crop production.

(b) Discuss the cultivation of oil palm under the following headings:
(i)  botanical name;
(ii) two varieties;
(iii) method of propagation;
(iv) soil requirement;
(v)  spacing on the field;
(vi) Diseases.  

(c) Enumerate six ways in which forest resources are important to the economy of West Africa.  

(d) What is apiculture? 

Détails de la réponse

(a)
Spacing and thinning are both practices used in crop production to control the plant population density. Spacing refers to the distance between plants at planting, while thinning refers to the removal of excess plants after germination. In spacing, the aim is to ensure that plants have enough space to grow to their full potential and avoid competition for resources such as water, nutrients, and sunlight. Thinning, on the other hand, is done to remove weaker or excess plants to allow the remaining plants to grow more vigorously and produce higher yields.

(b)
(i) Botanical name: The botanical name of oil palm is Elaeis guineensis.
(ii) Two varieties: The two main varieties of oil palm are the Dura and Pisifera.
(iii) Method of propagation: Oil palm is propagated through seeds or vegetative means, such as tissue culture or cuttings.
(iv) Soil requirement: Oil palm grows well in well-drained soils that are rich in organic matter and have a pH range of 4.5-7.0.
(v) Spacing on the field: Oil palm should be planted at a spacing of 9m x 9m or 10m x 10m to allow for adequate light penetration and optimal growth.
(vi) Diseases: Common diseases of oil palm include leaf rot, bud rot, and stem rot.

(c)
Six ways in which forest resources are important to the economy of West Africa are:
1) Timber production: Forests are a major source of timber for the construction and furniture industries.
2) Fuelwood: Forests provide fuelwood for domestic and industrial use.
3) Non-timber forest products: Forests provide non-timber forest products such as fruits, nuts, and medicinal plants that are important for local livelihoods and trade.
4) Ecotourism: Forests are a major attraction for ecotourism, which generates income for local communities.
5) Climate regulation: Forests play a key role in regulating the climate and mitigating the impacts of climate change.
6) Biodiversity conservation: Forests harbor a wide variety of plant and animal species, and their conservation is important for maintaining ecosystem services and biodiversity.

(d)
Apiculture is the practice of keeping and managing bees for their honey and other products such as beeswax, propolis, and royal jelly. It involves setting up beehives, providing food and water for the bees, monitoring their health and behavior, and harvesting the honey and other products. Apiculture is an important agricultural practice as it provides a source of income and food for people, and it also plays a crucial role in pollination, which is essential for the production of many crops.

(a) Write the full meaning of the acronyms of the following non-governmental agricultural organizations:
(i) WARDA;
(ii) IITA;
(iii) FAO;
(iv) ILCA. 

(b) Mention six ways in which agriculture is of benefit to rural communities. 

(c) List four liming materials used in agriculture. 

(d) Give four examples of sedimentary rocks. 

Détails de la réponse

(a)

1. WARDA stands for West Africa Rice Development Association, which is a research-based organization that aims to improve rice production in West Africa.
2. IITA stands for International Institute of Tropical Agriculture, which is a research-based organization that focuses on improving agricultural productivity and sustainability in sub-Saharan Africa.
3. FAO stands for Food and Agriculture Organization, which is a United Nations agency that works to eradicate hunger and promote sustainable agriculture globally.
4. ILCA stands for International Livestock Centre for Africa, which was a research-based organization that focused on improving livestock production in Africa, but has now been integrated into the International Livestock Research Institute (ILRI).

(b)

1. Six ways in which agriculture is of benefit to rural communities are:
1. Food security: Agriculture provides food for rural communities, reducing their dependence on external food sources.
2. Income generation: Agriculture provides a source of income through the sale of crops, livestock, and other agricultural products.
3. Employment opportunities: Agriculture creates job opportunities in various areas such as production, processing, and marketing.
4. Access to basic necessities: Agriculture provides rural communities with access to basic necessities such as food, shelter, and clothing.
5. Rural development: Agriculture contributes to the development of rural areas by improving infrastructure and access to services such as education and healthcare.
6. Environmental conservation: Agriculture can be practiced in a sustainable manner, contributing to the conservation of the environment and natural resources.

(c)

1. Four liming materials used in agriculture are:
• Limestone
• Calcium carbonate
• Dolomite
• Quicklime

(d)

1. Sedimentary rocks are formed by the accumulation and cementation of sediments over time. Four examples of sedimentary rocks are:
• Sandstone: a rock composed of sand-sized grains of mineral, rock, or organic material.
• Limestone: a rock composed primarily of calcium carbonate that forms from the accumulation of shells, coral, or other organic debris.
• Shale: a fine-grained sedimentary rock composed of clay minerals.
• [Fourth example]