WAEC SSCE - Biology - 2012
Question 1 Report
What is the benefit of thunder and lightning to farmers?
Answer Details
Thunder and lightning are natural phenomena that occur during thunderstorms. Thunderstorms usually bring rain, and rainwater is essential for crop growth. When lightning occurs, it splits nitrogen molecules in the air which then combine with oxygen to form nitrates. These nitrates dissolve in the rainwater and are deposited in the soil as it rains. Nitrates are an essential nutrient for plants and help them to grow better. Therefore, the benefit of thunder and lightning to farmers is that they add nitrates to the soil, which can lead to increased crop yields.
Question 2 Report
The following pairs of traits are examples of continuous and discontinuous variations respectively except
Answer Details
Question 3 Report
The diagram above is an illustration of an experimental setup to test the action of
yeast. What test would be used to confirm the nature of the gas given off at?
Answer Details
The test that would be used to confirm the nature of the gas given off in the experimental setup is to pass the gas through lime water. This is because lime water (Calcium hydroxide solution) reacts with carbon dioxide gas, which is one of the gases produced during yeast fermentation, to form a milky precipitate of calcium carbonate. If the gas given off by the yeast is carbon dioxide, then the lime water will turn milky when passed through it, confirming the nature of the gas.
Question 4 Report
Increasing adrenalin content of the blood would be expected to decrease the flow of blood to the
Question 5 Report
The area around the earth where life activities go on is referred to as
Answer Details
The area around the earth where life activities go on is referred to as the "biosphere". The biosphere is a combination of all living organisms, their habitats, and the ecological processes that sustain life. It includes the atmosphere (air), lithosphere (land), and hydrosphere (water), where living organisms interact with each other and the physical environment. The biosphere is essential for the survival and existence of all life on earth, and it plays a vital role in regulating the planet's climate, air quality, and water cycles.
Question 6 Report
Which of the following parts of the eye contains light sensitive cells?
Question 7 Report
Two plants with red flowers were back crossed, which of the following results indicate that the plants are heterozygous
red flowers, where red flowers are dominant?
Answer Details
If two plants with red flowers were backcrossed, it means that one parent is homozygous dominant for red flowers (RR) and the other parent is heterozygous for red flowers (Rr). Therefore, the possible genotypes of the offspring are: - 50% chance of getting Rr (heterozygous for red flowers) - 50% chance of getting rr (homozygous recessive for white flowers) If the plants are heterozygous for red flowers (Rr), the phenotype (physical appearance) ratio of their offspring will be 3:1 (red:white). This means that 75% of the offspring will have red flowers and 25% will have white flowers. Therefore, the answer is "75% red and 25% white" which is the option that indicates heterozygosity.
Question 8 Report
Plants with breathing roots are characteristic features of vegetation in
Answer Details
Plants with breathing roots are characteristic features of vegetation in saltwater swamp. In saltwater swamps, the soil is often waterlogged with high salt content, and oxygen levels can be low. Therefore, plants in these regions have evolved special adaptations to survive in such conditions, such as breathing roots, which are roots that grow above the water surface to allow the exchange of gases between the atmosphere and the root system. This adaptation helps the plants to obtain oxygen from the air and remove excess carbon dioxide and other gases from the roots. Examples of plants with breathing roots found in saltwater swamps include mangroves and some species of palms.
Question 9 Report
The muscle cell fluid of an athlete was tested immediately after a 1 O m race and was found to contain a high
concentration of lactic acid. Explain what could have caused this. The
Answer Details
The high concentration of lactic acid found in the muscle cell fluid of an athlete immediately after a 10 m race is likely caused by anaerobic respiration that occurred during the race. Anaerobic respiration is a process of cellular respiration that takes place in the absence of oxygen, producing lactic acid as a byproduct. During intense exercise, such as a sprint, the body may not be able to supply enough oxygen to the muscles, forcing them to switch to anaerobic respiration. This produces lactic acid which can accumulate in the muscles and cause fatigue and discomfort. Therefore, the most likely cause of the high concentration of lactic acid found in the athlete's muscle cell fluid is due to the anaerobic respiration of the muscles during the race.
Question 10 Report
The function of the convex lens in the correction of eye defects is to
Answer Details
The function of the convex lens in correcting eye defects is to converge light rays from far objects to focus their image on the retina. In people with myopia (short-sightedness), the image is focused in front of the retina, resulting in a blurred image. Placing a convex lens in front of the eye causes light rays to converge more, allowing the image to be focused on the retina. This corrects the vision so that distant objects appear clear.
Question 11 Report
In which of the following multicellular organisms is-interdependence of cells maintained?
Answer Details
The interdependence of cells refers to the mutual reliance of cells on each other for survival and functioning as a single organism. Among the given options, Volvox is a multicellular organism where interdependence of cells is maintained. In Volvox, each cell has a specific role to play, and they work together to perform various functions like movement, feeding, and reproduction. The cells are interconnected by cytoplasmic strands that allow them to communicate and share resources. The interdependence of cells ensures the proper functioning of the organism as a whole.
Question 12 Report
In the diagram, the function of the part labelled is to
Question 13 Report
A student dissecting am animal specimen discovered that it had two auricle and on ventricle. The animal is likely to a/an
Question 14 Report
The graph above represents the growth pattern of an animal. Which of the following groups of animals shows this
pattern of growth?
Answer Details
Question 15 Report
Which of the following statements is true about the ABO blood group system?
Answer Details
Question 16 Report
Which of the following factors exerts a major effect on the distribution of living organisms in the habitat?
Question 17 Report
The brightly coloured petals in some plants is an adaptive colouration for
Answer Details
Brightly colored petals in some plants serve as an adaptive coloration for pollination. Pollination is the process by which pollen grains are transferred from the male part of a plant to the female part of a plant, leading to fertilization and seed production. Brightly colored petals help to attract pollinators, such as bees, butterflies, and hummingbirds, which are attracted to the bright colors and sweet nectar of the flowers. The pollinators then transfer the pollen from one flower to another, ensuring cross-fertilization and genetic diversity. Therefore, the brightly colored petals are an adaptation of the plant to increase the chances of successful pollination and reproduction.
Question 18 Report
What name is given to a sudden change in a gene or chromosome?
Answer Details
A sudden change in a gene or chromosome is called a "mutation." Mutations are changes in the DNA sequence that can result in altered or new characteristics in an organism. They can occur spontaneously or be induced by external factors such as radiation or chemicals. Mutations can have different effects, ranging from neutral or harmful to beneficial, depending on the location and nature of the change. The occurrence of mutations is the basis of genetic diversity, which is essential for evolution and adaptation of species to changing environments.
Question 19 Report
Which of the following digestive enzymes would be greatly affected if the liver fails to
produce bile?
Answer Details
The correct answer is Lipase. Bile is produced by the liver and stored in the gallbladder. It helps in emulsifying fats into smaller droplets, which increases the surface area for lipase to act upon. Lipase is the enzyme responsible for the breakdown of fats into fatty acids and glycerol. Without sufficient bile to emulsify fats, the lipase enzyme will have a reduced surface area to act upon, thus leading to decreased digestion and absorption of fats. Therefore, if the liver fails to produce bile, the activity of lipase will be greatly affected.
Question 20 Report
The following are all examples of a simple reflex action, except
Answer Details
Walking is not an example of a simple reflex action. Simple reflex actions are those that occur automatically and involuntarily in response to a specific stimulus, without involving conscious thought. Examples of simple reflex actions include swallowing, sneezing, and blinking. However, walking is a complex action that involves the coordinated movement of muscles and the involvement of various parts of the brain, and is not a simple reflex action.
Question 21 Report
In which of the zones can very few organisms be found
Answer Details
The zone with very few organisms is zone IV, which is also known as the abyssal zone. This zone is characterized by very high pressure, very low temperatures, and complete darkness. The extreme conditions in this zone make it very difficult for organisms to survive, and as a result, only a few organisms are adapted to live in this zone. The organisms that can survive in the abyssal zone are often specially adapted to the extreme conditions, such as high pressure and low temperatures. They also have specialized feeding and reproductive mechanisms to cope with the lack of sunlight and low levels of organic matter.
Question 22 Report
In the structure of DNA, which of the following statements is true?
Question 23 Report
The bones of the legs of a six years old boy are observed to be weak and crooked. Which of the following elements
were deficient in his mother’s diet at pregnancy?
Answer Details
The element that is most likely to be deficient in the mother's diet during pregnancy and cause weak and crooked bones in the child is calcium and phosphorus. Calcium is an important element for bone formation and its deficiency can lead to a condition called rickets which results in weak and deformed bones. Phosphorus is also necessary for proper bone growth and development. Deficiency in both these elements during pregnancy can result in skeletal abnormalities in the developing fetus. Therefore, the most appropriate answer would be (c) Calcium and phosphorus.
Question 24 Report
Which of the following sequences is the correct evolutionary trend in plants?
Answer Details
The correct evolutionary trend in plants is Algae → liverworts → mosses → ferns. This is because algae, liverworts, mosses, and ferns represent the different stages in the evolution of plants. Algae are simple aquatic plants that lack specialized tissues for conducting water and nutrients. Liverworts and mosses evolved from algae and have specialized structures to absorb water and nutrients from their environment. Ferns evolved from mosses and have vascular tissue for conducting water and nutrients throughout the plant. Therefore, the correct sequence of the evolutionary trend is Algae → liverworts → mosses → ferns.
Question 25 Report
Which of the following instruments would be most appropriate in comparing the air pressure at different places in the habitat?
Answer Details
The most appropriate instrument for comparing air pressure at different places in the habitat is a barometer. A barometer is an instrument used to measure atmospheric pressure, and it can help in identifying high-pressure and low-pressure areas in the habitat. By comparing the readings of the barometer at different places in the habitat, we can determine which areas have higher or lower air pressure, which can have implications for weather patterns and other environmental conditions. The other instruments listed (hygrometer, photometer, and air pressure disc) measure humidity, light intensity, and air pressure changes, respectively, but they are not specifically designed to measure atmospheric pressure at different locations.
Question 26 Report
The primary cause of species endangerment is
Answer Details
The primary cause of species endangerment is disappearing habitats. This means that the natural habitats of many species are being destroyed or altered, which leads to a reduction in their population and can ultimately lead to their extinction. Human activities such as deforestation, urbanization, and pollution are the major drivers of habitat loss. As habitats disappear, species lose access to food, water, and shelter, making it difficult for them to survive. Therefore, conservation efforts are essential to protect habitats and prevent the extinction of species.
Question 27 Report
The epidermis of a leaf is considered an example of a tissue because the cells
Answer Details
The epidermis of a leaf is considered an example of a tissue because the cells all possess a similar structure and function. The epidermal cells are tightly packed and flattened to form a continuous layer that covers the entire surface of the leaf. They are covered by a waxy cuticle, which helps to prevent water loss through the leaf surface. The main function of the epidermis is to protect the leaf from external damage and regulate the exchange of gases, such as carbon dioxide and oxygen, between the leaf and the environment. Therefore, the epidermis of a leaf is considered a tissue because it is composed of a group of similar cells that perform a specific function.
Question 28 Report
Bees are of great importance to the farmer because they
Answer Details
Bees are important to farmers because they pollinate flowers. When bees fly from flower to flower collecting nectar, they transfer pollen from the male part of the flower to the female part, which fertilizes the plant and allows it to produce fruit or seeds. This is crucial for the reproduction of many crops, including fruits, vegetables, and nuts. Without bees, the yields of these crops would be significantly reduced, and in some cases, the plants would not be able to produce fruit or seeds at all. While bees do produce honey, this is not their primary role in agriculture.
Question 29 Report
Which of the following diseases is transmittable through genes?
Answer Details
Sickle cell anemia is the disease that is transmittable through genes. It is a genetic disorder caused by a mutation in the hemoglobin gene. People with sickle cell anemia inherit two copies of the mutated gene, one from each parent, and this causes the hemoglobin in their red blood cells to be abnormal. The abnormal hemoglobin causes the red blood cells to take a crescent or sickle shape, which can block blood flow, leading to pain, organ damage, and an increased risk of infections.
Question 30 Report
The organism at the organ level of organisation of life is
Answer Details
Among the options given, the organism at the organ level of organization of life is "Ginger". Ginger is a plant that exhibits organ level of organization. It has different organs such as roots, stem, leaves, and flowers that have specialized functions. The roots of ginger are used for storage of food and absorption of water and nutrients from the soil, the stem provides support for the leaves and flowers, the leaves are responsible for photosynthesis, and the flowers are involved in reproduction. On the other hand, Euglena and Spirogyra are unicellular organisms that exhibit cellular level of organization, and Tapeworm is a multicellular organism that exhibits tissue level of organization.
Question 32 Report
Which of the following structures in a flower develops into the seed?
Answer Details
The structure in a flower that develops into the seed is the ovule. The ovule is located inside the ovary of the flower and contains the female gamete. After pollination and fertilization, the ovule develops into a seed which contains an embryo that will develop into a new plant. The integument is the protective covering of the ovule and becomes the seed coat after fertilization. The testa is the protective outer covering of the seed.
Question 33 Report
Squirrels easily kill some trees because
Answer Details
Squirrels can easily kill some trees because they gnaw the bark and destroy it. The bark is essential to the tree's survival because it contains the phloem and xylem, which transport food and water throughout the tree. Without bark, the tree cannot transport these essential materials, and it will eventually die. Squirrels gnaw the bark for various reasons, such as to obtain food or create a nest, but the result is often fatal for the tree.
Question 34 Report
The diagram above is an illustration of the human excretory system. Which of the labelled parts contains the
highest amount of nitrogenous waste?
Answer Details
Label IV, the kidney, contains the highest amount of nitrogenous waste. The kidneys are responsible for filtering and removing waste products such as urea and uric acid from the blood. These nitrogenous wastes are produced as a result of protein metabolism in the body, and the kidneys work to remove them from the blood and excrete them in the urine. Therefore, since the kidneys are responsible for the removal of nitrogenous waste, they contain the highest amount of it among the labelled parts in the diagram.
Question 37 Report
The science of life is referred to as
Answer Details
The science of life is referred to as biology. Biology is the study of living organisms, including their structure, function, growth, evolution, and distribution. It encompasses a wide range of topics, from the smallest cells to the largest ecosystems, and provides us with knowledge about the diversity of life on earth, the interrelationships between organisms, and their interaction with the environment. Biology is an important field of study because it helps us to better understand the world around us and to develop new technologies and medical treatments based on our knowledge of living organisms.
Question 38 Report
The following are abiotic components of the ecosystem except
Answer Details
The answer is bacteria. Bacteria are living organisms and belong to the biotic components of the ecosystem. Biotic components of the ecosystem include all living things such as plants, animals, fungi, and microorganisms. Abiotic components, on the other hand, include all non-living things in the ecosystem such as water, air, soil, rocks, sunlight, wind, and topography. Therefore, is the correct answer as it is a living organism and not an abiotic component of the ecosystem.
Question 39 Report
Which of the following processes occurs in the second phase of meiosis?
Answer Details
The correct answer is "homologous chromosomes separate". Meiosis is a type of cell division that occurs in sexually reproducing organisms, and it involves two rounds of cell division. The first phase of meiosis is called meiosis I, and it involves the separation of homologous chromosomes. In the second phase, meiosis II, the sister chromatids of each chromosome separate, resulting in four haploid daughter cells. Therefore, the process that occurs in the second phase of meiosis is the separation of sister chromatids, and this is what leads to the formation of four haploid daughter cells.
Question 40 Report
The main raw materials required for photosynthesis are
Answer Details
The main raw materials required for photosynthesis are carbon dioxide and water. During photosynthesis, plants use energy from sunlight to convert carbon dioxide from the air and water from the soil into glucose (a type of sugar) and oxygen. This process occurs in the chloroplasts of plant cells, which contain the pigment chlorophyll that absorbs light energy. The oxygen produced during photosynthesis is released into the atmosphere as a byproduct, while the glucose serves as the plant's source of energy for growth and development.
Question 41 Report
Which of the following substances must be present in the soil for growth of a healthy green plant?
Answer Details
Magnesium ions must be present in the soil for the growth of a healthy green plant. Magnesium is an essential mineral nutrient for plants and is involved in many important plant functions, such as photosynthesis, enzyme activation, and the production of chlorophyll. Chlorophyll is the pigment responsible for the green color of leaves and is necessary for photosynthesis. Without magnesium, plants cannot produce enough chlorophyll, which can result in yellowing leaves, stunted growth, and poor yields. While the other options listed are important for plant growth, magnesium ions are particularly crucial for a healthy green plant.
Question 42 Report