WAEC SSCE - Agricultural Science - 2019 (Objective)

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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%.

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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.

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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.

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