WAEC SSCE - Biology - 2017
Question 1 Report
An example of osmosis in plants is the
Answer Details
An example of osmosis in plants is the absorption of water from the soil by the root. Osmosis is the movement of water molecules from an area of high water concentration to an area of low water concentration through a selectively permeable membrane. In plants, the root hairs, which are thin extensions of the root, have a higher concentration of solutes (dissolved substances) than the surrounding soil. As a result, water moves from the area of high water concentration in the soil to the area of low water concentration in the root hairs via osmosis. This is an essential process for the plant to absorb the water and nutrients it needs for growth and survival.
Question 2 Report
Which of the following organisms cannot exist freely on its own?
Answer Details
The organism that cannot exist freely on its own is Plasmodium. Plasmodium is a parasitic protozoan that causes malaria in humans. It cannot survive outside of its host, which is typically a mosquito or a human. Plasmodium has a complex life cycle that involves both sexual and asexual reproduction, and it requires a specific set of environmental conditions to complete its life cycle. Once inside the host, the parasite invades the host's red blood cells and feeds on hemoglobin, which can cause severe anemia and other complications. Therefore, Plasmodium is entirely dependent on its host for survival and cannot exist freely on its own.
Question 3 Report
The diagram above is an illustration of the urinary tubule in a mammal. Which of the following substances is greater in concentration in the part labelled IV when compared to that part labelled I?
Answer Details
The substance that is greater in concentration in the part labeled IV when compared to that part labeled I is Urea. The urinary tubule is a part of the renal system and is responsible for filtering waste products from the blood and reabsorbing important substances back into the bloodstream. In the diagram, the part labeled I represents the beginning of the urinary tubule, where the blood is filtered to remove waste products. The part labeled IV represents the end of the tubule, where the final concentration of waste products is determined. Urea is a waste product produced by the liver and is present in high concentrations in the blood. As the blood passes through the urinary tubule, some of the urea is reabsorbed back into the bloodstream, but most of it continues to be filtered and concentrated in the part labeled IV. The concentration of urea in the part labeled IV is therefore greater than that in the part labeled I. Lipids, glucose, and uric acid are not primarily waste products of the renal system, but they can be filtered and reabsorbed in small amounts along with urea and other waste products.
Question 4 Report
Which of the following types of placentation is not common amongst syncarpous pistils?
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Question 5 Report
The complex energy-rich organic matter which living organisms need for life is
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The complex energy-rich organic matter which living organisms need for life is food. Food provides the energy and nutrients that living organisms need to carry out their metabolic processes, grow, and reproduce. Food contains various molecules such as carbohydrates, proteins, and fats that the body breaks down into simpler forms through digestion and then utilizes to provide energy and building blocks for the body's cells. Without food, organisms would not be able to survive as they would not have the necessary energy and resources to carry out life-sustaining activities.
Question 6 Report
Which of the following is NOT characteristic of social insects?
Answer Details
The characteristic that is NOT associated with social insects is "All members are identical". In social insects, there is division of labor where each member of the colony has a specific task to perform, such as foraging, building the nest, caring for the young, or defending the colony. The members dwell in the same habitat, which is typically the nest or colony, and some members protect the queen, who is responsible for producing offspring. However, social insects are not identical. They may have different physical characteristics or perform different tasks within the colony. For example, in a bee colony, worker bees are physically different from drones, and they have different roles and responsibilities within the colony. Similarly, in an ant colony, soldiers are larger and have a different body shape than workers. In summary, social insects are not identical, but they do exhibit division of labor, live in the same habitat, and have some members that protect the queen.
Question 7 Report
Which of the following characters is not a morphological variation?
Question 8 Report
The teeth which are absent in the young of the organism whose dentition is shown above is labelled
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Question 9 Report
Soil permeability refers to
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Soil permeability refers to how easily water passes through the soil. It is a measure of the rate at which water can move through soil pores or spaces between soil particles. Soils with high permeability allow water to pass through quickly, while soils with low permeability restrict the movement of water. Permeability is determined by various factors, such as soil texture, structure, compaction, and organic matter content. Coarse-textured soils with larger pore spaces, such as sandy soils, generally have high permeability, while fine-textured soils with smaller pore spaces, such as clay soils, have low permeability. Soil permeability is an important property that affects plant growth and water availability, as it influences the rate at which water can move through soil and reach plant roots.
Question 10 Report
Which of the following actions does not occur during exhalation in man?
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Question 11 Report
Which of the following resources cannot be renewed?
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Petroleum is a resource that cannot be renewed. Petroleum, also known as crude oil, is a fossil fuel that was formed millions of years ago from the remains of plants and animals. It is a non-renewable resource because it takes millions of years to form and cannot be replenished at the same rate it is being used. Once all the petroleum reserves have been extracted, there will be no more left. This is in contrast to renewable resources such as air, food crops, and soil, which can be replenished naturally over time.
Question 12 Report
Which of the labelled parts of the diagram of the part of the human skeleton articulates with the head of the trochlea to form a hinge joint?
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Question 13 Report
Which of the following groups of organisms do not have members that can be called autotrophs?
Answer Details
The group of organisms that do not have members that can be called autotrophs is Fungi. Autotrophs are organisms that are able to synthesize their own food using simple inorganic substances and an external energy source, such as sunlight. Autotrophs include plants, some protists, and some bacteria. Fungi, on the other hand, are heterotrophic organisms that obtain their nutrition by decomposing dead organic matter or by forming mutualistic relationships with other organisms. They do not have the ability to carry out photosynthesis or produce their own food, and therefore cannot be called autotrophs. In summary, fungi are not autotrophs, while protists, mosses, and Chlorophyta all have members that can be considered autotrophs.
Question 14 Report
Which of the following pairs of organisms is in a mutualistic relationship?
Answer Details
The pair of organisms that is in a mutualistic relationship is the Hermit crab and Sea anemone. In this relationship, the hermit crab provides protection and transportation for the sea anemone, while the sea anemone provides the hermit crab with defense against predators. The sea anemone attaches itself to the shell of the hermit crab and uses its stinging tentacles to deter potential predators. In return, the hermit crab provides the sea anemone with food and a means of transportation to new food sources. Therefore, the hermit crab and sea anemone have a mutualistic relationship because both organisms benefit from the interaction.
Question 16 Report
The number of individuals that the environment can support over a long period of time is its
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Question 17 Report
Deamination of amino acids in the liver produces
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Deamination of amino acids in the liver produces urea. When proteins are broken down in the body, the amino acids are transported to the liver for processing. In the liver, enzymes remove the amino group from the amino acids, a process called deamination. This produces ammonia, which is toxic to the body. To get rid of the ammonia, the liver converts it into a less toxic compound called urea, which can be safely transported to the kidneys for excretion in urine. Therefore, the liver plays a crucial role in removing excess nitrogen from the body, and the production of urea is an important part of this process.
Question 18 Report
Which of the following function is associated with calcium in plants? Formation of
Answer Details
The function associated with calcium in plants is the formation of the cell wall. Calcium is an important nutrient that is required for the proper development and strengthening of the cell wall in plant cells. It plays a crucial role in the formation of pectin, a component of the cell wall that helps to hold the cell walls of adjacent cells together. This allows the plant to maintain its structure and also helps to protect it from environmental stresses like wind and water. Additionally, calcium helps to regulate the transport of other nutrients and water into and out of the cell, and it is involved in the activation of enzymes that are important for growth and development.
Question 19 Report
Which of the following statements is not associated with pyramids of energy?
Answer Details
More accurate comparisons of trophic levels is not associated with pyramids of energy. Pyramids of energy are graphical representations of the flow of energy through an ecosystem, showing the amount of energy transferred from one trophic level to the next. While pyramids can be used to compare the efficiency of energy transfer between trophic levels and make comparisons of pyramids for different ecosystems, they do not necessarily provide more accurate comparisons of trophic levels. The accuracy of the comparison depends on various factors such as the method used to measure the energy flow and the precision of the data used to construct the pyramid.
Question 20 Report
The diagram above shows the dentition of an organism. What organism is this?
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Question 21 Report
When viewing an object that is close to the human eye, the
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When viewing an object that is close to the human eye, the eye lens becomes fat. The process of changing the shape of the eye lens to focus on objects at different distances is called accommodation. When the eye is focusing on a nearby object, the ciliary muscles in the eye contract, which causes the suspensory ligaments to relax. This, in turn, allows the eye lens to become more rounded and thicker, which increases its refractive power. The increased curvature of the eye lens allows the eye to bend the light more, so that the light rays converge and focus on the retina, producing a clear and sharp image. This process of accommodation is necessary to see objects clearly at different distances, and it is an automatic process controlled by the brain. Therefore, when viewing an object that is close to the human eye, the eye lens becomes fat to focus the light rays and produce a clear image on the retina.
Question 22 Report