WAEC SSCE - Biology - 2015
Question 2 Report
Ability of the human eye to focus images accurately on the retina is called
Answer Details
The ability of the human eye to focus images accurately on the retina is called accommodation. This is the process by which the lens of the eye changes shape to adjust the focal length of the eye and ensure that objects at different distances are focused correctly on the retina. When we look at a distant object, the ciliary muscles in the eye relax, making the lens thinner and flatter. When we look at a nearby object, the ciliary muscles contract, making the lens thicker and more curved. This change in the shape of the lens is what allows us to see objects at different distances clearly.
Question 3 Report
Which of the following natural resources is most readily available to all organisms?
Question 4 Report
A person had an accident that affected the skull but not the nose and later lost the sense of smell. The accident must have a affected the
Answer Details
The sense of smell is facilitated by olfactory receptors located in the nose. When odors are detected, these receptors send signals to the olfactory lobes of the brain, which interprets and processes the information as the sense of smell. Therefore, if a person loses their sense of smell after a head injury that affected the skull but not the nose, it is likely that the accident caused damage to the olfactory lobes of the brain. So, the correct option is (b) olfactory lobes of the brain.
Question 5 Report
A plant that commonly undergoes vegetative propagation by means of leaves is
Answer Details
The plant that commonly undergoes vegetative propagation by means of leaves is Bryophyllum. Bryophyllum is a succulent plant that produces plantlets at the edges of its leaves. These plantlets fall off the leaf, take root in the soil, and grow into new plants. This method of asexual reproduction through leaves is known as leaf-budding. The new plants produced through this method are genetically identical to the parent plant.
Question 6 Report
In explaining the term camouflage, to a class, the diagram above show four varieties, P, Q, R, and S of the same species of fish living amongst water plants in a river were used
Which of the varieties is likely to decrease most in number if a predatory fish is introduced into the river?
Answer Details
Question 7 Report
Blood pressure is higher in the arteries as a result of
Answer Details
Blood pressure is higher in the arteries as a result of contraction and relaxation. Arteries are the blood vessels that carry oxygenated blood away from the heart to other parts of the body. The heart pumps blood into the arteries, and the contraction of the heart muscles forces blood into the arteries, creating pressure in them. This pressure is known as systolic blood pressure. When the heart relaxes, the pressure in the arteries decreases, which is known as diastolic blood pressure. The alternating contraction and relaxation of the heart muscles along with the elasticity of the arterial walls maintain the blood pressure in the arteries. This pressure is necessary for proper circulation of blood and delivery of oxygen and nutrients to the body tissues.
Question 8 Report
In explaining the term camouflage, to a class, the diagram above show four varieties, P, Q, R, and S of the same species of fish living amongst water plants in a river were used
Which of the varieties is most likely to outlive the others?
Answer Details
Question 9 Report
Soil erosion could be prevented by
Answer Details
Soil erosion can be prevented by cover-cropping. Cover-cropping involves planting a crop on the land during the fallow period to cover the soil and protect it from erosion caused by wind or rain. The roots of the cover crop hold the soil in place and help to build soil health by adding organic matter. Cover crops also improve soil fertility, reduce soil compaction, and suppress weeds. This method is a sustainable and effective way to protect the soil from erosion and maintain the health of the land for long-term productivity. Flooding a farmland can cause more harm than good as it can wash away topsoil and nutrients. Deforestation and leaving the soil bare also contribute to soil erosion as they leave the soil exposed to wind and rain.
Question 10 Report
A woman with blood group A gives birth to a child with blood group O. Which of the following blood groups cannot belong to the father?
Answer Details
Question 11 Report
Use the diagram above to answer this question.
What are the genotypes of the parents if the gene for skin colour is H?
Answer Details
The diagram above shows a Punnett square used to predict the possible genotypes of the offspring of a cross between a spotted leopard (Hh) and a black panther (hh) with the gene for skin colour represented by the letter H. The possible genotypes of the offspring are shown in the boxes formed by the Punnett square. Looking at the Punnett square, it can be observed that the genotypes of the parents are Spotted Leopard Hh and Black Panther hh, since each parent contributes one allele to each offspring. Therefore, the correct answer is "Spotted Leopard Hh Black Panther hh".
Question 12 Report
Which of the following statements about protoplasm of a cell is not correct? It
Answer Details
The statement that is not correct is "consists the nucleus only". This is because the protoplasm of a cell is the living substance that makes up the entire cell, including the nucleus, cytoplasm, and cell organelles. The nucleus is just one component of the protoplasm, which also includes the cytoplasm and cell organelles such as mitochondria, ribosomes, and the endoplasmic reticulum. Therefore, the correct statement would be "comprises of the nucleus, cytoplasm, and cell organelles".
Question 13 Report
According to Mendel's first law of inheritance, segregation of genes occur when
Question 14 Report
The following organisms have structures for movement except
Answer Details
Among the given options, Spirogyra is the organism that does not have structures for movement. Spirogyra is a type of algae that has a filamentous structure and does not possess any specialized structures such as cilia or flagella for movement. Amoeba moves by the extension and contraction of its pseudopodia, Paramecium moves by the coordinated action of cilia, and Volvox moves by the synchronized beating of flagella on its surface. Hence, the correct answer is Spirogyra.
Question 16 Report
Which of the following statements about sex-linked characters is not true?
Question 17 Report
The diagram above illustrates a part of the mammalian skeleton . use it to answer this this question
The part of the skeleton illustrated in the diagram is the
Answer Details
The part of the mammalian skeleton illustrated in the diagram is the cervical vertebrae. This is because the cervical vertebrae are the seven vertebrae that make up the neck of the mammal, and the diagram shows seven vertebrae with the characteristic features of cervical vertebrae, such as a small body, a large vertebral foramen, and transverse foramina for the passage of blood vessels.
Question 18 Report
The diagram above is illustration of a crocodile. Use it to answer this question.
Two characteristic features of the class to which the crocodile belongs are labelled
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Question 19 Report
The following diagram above show the sequence of events in early cell division. Study the diagram and answer the question.
In which of the following cells is this divisin likely to take plce?
Answer Details
Question 20 Report
Oil applied to the surface of water kills the larvae of mosquitoes through
Answer Details
Oil applied to the surface of water kills the larvae of mosquitoes through suffocation. Mosquito larvae breathe air through a tube called a siphon, which they use to reach the surface of the water to breathe. When a layer of oil is applied to the surface of the water, it creates a film that covers the siphon and prevents the larvae from accessing air. As a result, the larvae suffocate and die. This method is often used as a non-toxic and environmentally friendly way to control mosquito populations.
Question 21 Report
A student used the following steps in testing for a non-reducing sugar.
I. added Benedict's solution to the sugar solution
ll. added dilute hydrochloric acid to the sugar and boiled it;
lll. added sodium hydroxide solution to the solution in ll. and boiled;
IV. added Benedict's solution to the cooled solution in lll.
Use this information above to answer the question.
What is the importance of step ll in the testing process? To
Answer Details
Question 22 Report
A person suffering from obstruction of the bile duct is advised not to eat fats and oil because
Answer Details
The correct answer is: "bile emulsifies fat and oil." Bile is a digestive fluid produced by the liver and stored in the gallbladder. It helps in the digestion and absorption of fats and oils in the small intestine. Bile contains bile salts which act as emulsifying agents. Emulsification is the process by which large fat globules are broken down into smaller droplets, making it easier for enzymes to break down the fats and for them to be absorbed into the bloodstream. When the bile duct is obstructed, bile cannot flow into the small intestine, leading to a decrease in the amount of bile available for digestion. As a result, the digestion and absorption of fats and oils become compromised, leading to symptoms such as abdominal pain, bloating, and diarrhea. Therefore, people with bile duct obstruction are advised to avoid consuming fats and oils to prevent worsening of their symptoms.
Question 24 Report
A student used the following steps in testing for a non-reducing sugar.
I. added Benedict's solution to the sugar solution
ll. added dilute hydrochloric acid to the sugar and boiled it;
lll. added sodium hydroxide solution to the solution in ll. and boiled;
IV. added Benedict's solution to the cooled solution in lll.
Use this information above to answer the question.
Why did the student add the dilute hydrochloric acid to the sugar solution in step ll? To
Answer Details
The student added dilute hydrochloric acid to the sugar solution in step ll to hydrolyze the non-reducing sugar into its reducing sugar components. This step breaks down the non-reducing sugar into smaller reducing sugar units that can then react with Benedict's solution in the subsequent steps. Without hydrolyzing the non-reducing sugar, it would not be able to react with Benedict's solution and give a positive result. Therefore, the addition of hydrochloric acid is an important step in testing for non-reducing sugars.
Question 25 Report
Which of the following resources is non-renewable?
Answer Details
A non-renewable resource is a natural resource that cannot be replaced once it is used up. Among the given options, the mineral deposit is a non-renewable resource because once it is extracted from the earth and used up, it cannot be replenished. Forest reserves and wildlife can be conserved and replenished with proper management and conservation efforts, while water is a renewable resource that can be replenished through the water cycle.
Question 26 Report
Which of the following organs of the alimentary canal is not correctly matched with its function?
Answer Details
The organ that is not correctly matched with its function in the given options is the Appendix - releases enzymes. The Appendix is actually a small, finger-shaped pouch that is located near the junction of the small and large intestines. While the function of the appendix is not entirely clear, it is believed to play a role in immune function and may also have a role in maintaining a healthy balance of bacteria in the gut. The other options are correctly matched with their functions. The gallbladder stores bile, which is produced by the liver and helps to digest fats in the small intestine. The liver also plays a role in storing glycogen, which is a form of glucose that can be used by the body for energy when needed. Teeth are responsible for mechanically breaking down food by grinding and crushing it, which makes it easier to swallow and digest.
Question 27 Report
Which of the following features could be used to determine the growth of a seedling?
Answer Details
The feature that could be used to determine the growth of a seedling is the length of the radicle. The radicle is the first part of the seedling to emerge during germination, and it is the embryonic root of the plant. As the radicle grows, it anchors the seedling in the soil and begins to absorb water and nutrients from the surrounding environment. Therefore, the length of the radicle is a good indicator of how well the seedling is growing and developing. The other options - number of flowers, number of leaves, and length of flowers - are not as good indicators of seedling growth. These features are more relevant to the reproductive phase of the plant's life cycle, and they may not be present or fully developed in a young seedling. Therefore, the length of the radicle is the best feature to use when determining the growth of a seedling.
Question 28 Report
Which of the following cells is a specialized cell?
Answer Details
A specialized cell is a cell that has a specific structure and function to perform a particular task within an organism. Of the options given, the cell that is a specialized cell is the guard cell. The guard cell is a specialized cell found in the epidermis of leaves, which regulates the opening and closing of stomata, tiny pores on the surface of leaves that allow for gas exchange. The guard cell has a kidney-shaped structure with a thickened inner wall and a thinner outer wall. When water enters the guard cell, it swells, and the thin outer wall expands, causing the guard cell to bend and create an opening between the two cells. This opening allows for gas exchange between the plant and its environment. The amoeba and Plasmodium are unicellular organisms that do not have specialized cells as they perform all the necessary functions within a single cell. The meristematic cell is a type of plant cell that has the ability to divide and differentiate into various types of plant cells, but it is not considered a specialized cell as it does not have a specific structure and function to perform a particular task. In summary, the guard cell is a specialized cell because of its specific structure and function to regulate the opening and closing of stomata in plant leaves.
Question 29 Report