WAEC SSCE - Biology - 1993
Question 1 Report
The use of predators or parasites to control pests in the farm is known as
Answer Details
The use of predators or parasites to control pests in the farm is known as biological control. This involves introducing natural enemies of the pest to the farm to control their populations, rather than using chemical pesticides or other methods. The natural enemies can be predators, parasites, or pathogens that attack the pests and help to reduce their numbers. Biological control is an environmentally friendly and sustainable way to control pests, as it does not harm the ecosystem or affect other beneficial organisms.
Question 2 Report
The organ which is sensitive to light in Euglena is the
Answer Details
The organ in Euglena that is sensitive to light is the eye spot. The eye spot, also known as the stigma, is a small, pigmented organelle located near the base of the flagellum. It contains a photoreceptor pigment that enables the organism to sense the direction of light and adjust its movement accordingly.
Question 3 Report
Which of the following mineral salts is a trace element?
Answer Details
Zinc is a trace element among the listed mineral salts. A trace element is a mineral that is required by the body in very small amounts, typically less than 100 milligrams per day. Zinc is an essential mineral that plays a crucial role in many bodily processes, including immune function, wound healing, and DNA synthesis. Although it is only required in small amounts, it is still an important mineral that the body needs to function properly. The other minerals listed, such as carbon, hydrogen, potassium, and calcium, are also important for various bodily processes, but they are not classified as trace elements.
Question 4 Report
The swarming especially at the beginning of the rainy season is a courtship behaviour shown by
Answer Details
Question 5 Report
Which of the following structures are adjusted in focusing the image of a
distant or near object on the retina?
Answer Details
Question 6 Report
Which of the following water pollutant may contain organisms that cause dysentery?
Answer Details
The water pollutant that may contain organisms that cause dysentery is sewage. Sewage is the wastewater that contains human and animal feces, as well as urine, so it may contain pathogenic microorganisms such as bacteria, viruses, and parasites that can cause diseases like dysentery. Dysentery is a type of gastrointestinal infection that results in severe diarrhea with mucus and blood in the stool. It is typically caused by the bacteria Shigella or Entamoeba histolytica, which are commonly found in human feces. The other water pollutants listed in the options, such as pesticides, fertilizers, industrial wastes, and crude oil, may contain harmful chemicals that can contaminate water and affect aquatic life or human health, but they do not necessarily contain microorganisms that cause dysentery.
Question 7 Report
Which of the following is a function of the chromosome?
Answer Details
The function of the chromosome is the transmission of hereditary traits. Chromosomes are thread-like structures that carry genetic information in the form of genes, which are made up of DNA. During cell division, chromosomes are replicated and passed on to daughter cells, ensuring that genetic information is transmitted from one generation to the next. The transmission of hereditary traits is essential for the continuity of life and the survival of species. Therefore, is the correct answer. Options (b), (c), (d), and (e) are not functions of the chromosome.
Question 8 Report
The first scientist to describe the cell was
Answer Details
The first scientist to describe the cell was Robert Hooke. In 1665, he observed cork cells using a microscope and described them as "a great many little Boxes, or Cells." This was the first time cells had been observed and named. While other scientists, such as Anton van Leeuwenhoek and Matthias Schleiden, also made significant contributions to our understanding of cells, Robert Hooke is credited with being the first to use the term "cell" and to recognize that cells were the basic unit of life.
Question 9 Report
The respiratory organ found in the cockroach is the
Answer Details
The respiratory organ found in a cockroach is the trachea. The trachea is a network of tubes that is responsible for carrying air to and from the body tissues of the cockroach. These tubes are made up of chitin and are connected to the outside environment through openings called spiracles. The spiracles allow air to enter and exit the tracheal system. Inside the tracheae, gases are exchanged between the air and the body tissues of the cockroach through diffusion, which is facilitated by a system of smaller tubes called tracheoles. This allows the cockroach to obtain the oxygen it needs for respiration and to release carbon dioxide as a waste product.
Question 10 Report
Which of the following best describes a marine habitat? A large body of water A
Answer Details
A marine habitat can be best described as a large body of water with a high concentration of salt. This type of habitat is characterized by its saltwater environment, which is home to a diverse array of plant and animal species. The high concentration of salt in the water is what differentiates marine habitats from other types of aquatic environments, such as freshwater habitats. Marine habitats can be found in various locations, such as oceans, seas, and coral reefs. They are essential for sustaining the life of many marine organisms, including fish, sharks, whales, and sea turtles, among others.
Question 11 Report
The conditions that ensure successful exchange of gases in multicellular organisms include the following except
Answer Details
The exchange of gases in multicellular organisms is a vital process to obtain oxygen and get rid of carbon dioxide. For successful gas exchange, there are certain conditions that need to be met. The first condition is a concentration gradient across the respiratory surface. This means that there must be a difference in the concentration of gases between the internal and external environments. Oxygen should be more concentrated outside while carbon dioxide should be more concentrated inside. This difference in concentration allows for the diffusion of gases across the respiratory surface. The second condition is the presence of a thin membrane as the respiratory surface. The respiratory surface should be thin to allow for the easy diffusion of gases across it. This ensures that gases can quickly move in and out of the body. The third condition is the last transportation of absorbed gases. After gases have diffused across the respiratory surface, they should be transported to the cells that need them. This transportation is done through the circulatory system, which moves gases from the respiratory surface to the cells and back again. The fourth condition is the presence of a large surface area of the respiratory organ. The larger the surface area, the more space there is for gas exchange to occur. This is important for animals that require a lot of oxygen, like birds or mammals. The fifth condition is the absence of a small, dry surface area of the respiratory organ. This option is incorrect because a dry surface area would make it difficult for gases to diffuse across it. The respiratory surface should be moist to allow for the easy diffusion of gases. In summary, successful exchange of gases in multicellular organisms requires a concentration gradient, a thin membrane, transportation of absorbed gases, a large surface area of the respiratory organ, and a moist respiratory surface.
Question 12 Report
The parts labelled IV, V and VI respectively are the
Question 13 Report
A climax community is characterised by
Answer Details
A climax community refers to the final stage of succession, where a community of plants and animals have reached a stable state of balance with the environment. The correct option is: "a stable composition of plant and animal species." A climax community is characterized by a diverse range of plant and animal species that have adapted to the prevailing climatic and soil conditions. The community has a complex food web and nutrient cycling processes. In a climax community, the species composition remains relatively stable over time and the community can persist for hundreds or thousands of years without significant disturbance. In summary, a climax community is an equilibrium state of a stable and diverse community of plants and animals that have evolved over time to create a self-sustaining and resilient ecosystem.
Question 14 Report
The property of clay soil that prevents it from supporting thick vegetation is its
Answer Details
Clay soil has small particles that are closely packed together, which creates a high density and low porosity soil. This means that the soil particles have a high attraction to each other, and they hold onto water tightly, making it difficult for water and air to move through the soil. This can lead to waterlogging, a condition where water accumulates on the soil surface, making it difficult for plant roots to breathe and grow. The property of clay soil that prevents it from supporting thick vegetation is its tendency of becoming waterlogged.
The part labelled I is theQuestion 16 Report
During the process of breathing, volume and pressure changes occur as a result of the movement of the parts labelled
Answer Details
Question 17 Report
Which of the following blood vessels carries oxygenated blood into the heart?
Answer Details
The blood vessel that carries oxygenated blood into the heart is the pulmonary vein. The pulmonary vein is responsible for transporting blood that has picked up oxygen in the lungs and returning it to the left atrium of the heart. The left atrium then pumps the oxygen-rich blood into the left ventricle, which contracts and sends the blood out to the body through the aorta. The other blood vessels listed in the options either carry deoxygenated blood (such as the pulmonary artery) or return blood to the heart that has already been circulated through the body (such as the anterior and posterior vena cava).
Question 18 Report
How would you describe the position of the ovary in relation to the
receptacle?
Answer Details
The position of the ovary in relation to the receptacle is a way of describing the structure of a flower. - Superior ovary: When the ovary is located above the attachment point of the other floral parts, it is called a superior ovary. - Inferior ovary: When the ovary is located below the attachment point of the other floral parts, it is called an inferior ovary. - Semi-inferior ovary: When the ovary is partially below and partially above the attachment point of the other floral parts, it is called a semi-inferior ovary. Therefore, the correct answer to the question is: The position of the ovary in relation to the receptacle is referred to as "superior" when the ovary is located above the attachment point of the other floral parts.
Question 19 Report
Which of the following is a similarity between a typical animal cell and a typical plant cell? Presence of
Answer Details
The presence of a cell membrane is a similarity between a typical animal cell and a typical plant cell. A cell membrane, also known as the plasma membrane, is a thin layer that encloses the cell, separating the internal environment from the external environment. Both animal and plant cells have a cell membrane that controls the movement of substances in and out of the cell, maintains the cell shape and structure, and protects the cell from external factors.
Question 20 Report
The division of labour in social insects is an example of
Answer Details
The division of labor in social insects, such as ants and bees, is an example of behavioral adaptation. Behavioral adaptation refers to a change in the behavior of an organism that allows it to better survive and reproduce in its environment. Social insects divide labor among members of the colony based on their specialized abilities and roles, such as foraging for food, caring for the young, or defending the nest. This specialization of labor allows the colony to be more efficient and successful in meeting the needs of the group as a whole.
Question 21 Report
The part labelled VII is the
Answer Details
The part labelled VII is the diaphragm. The diaphragm is a sheet of muscle that separates the thoracic and abdominal cavities. It plays an important role in breathing by contracting and relaxing to change the volume of the thoracic cavity, causing air to move in or out of the lungs.
Question 22 Report
Which of the following substances cannot control the growth of harmful micro organisms?
Answer Details
Isotonic sugar solution cannot control the growth of harmful microorganisms. Isotonic sugar solution has the same concentration of solutes as the microorganisms and as a result, it does not create an environment that is unfavorable for their growth. The other options listed have properties that can control the growth of harmful microorganisms. For example, antibiotics target specific types of bacteria, hypertonic salt solution creates a high concentration of salt that causes the microorganisms to lose water and disinfectants and antiseptics kill or inhibit the growth of microorganisms.
Question 23 Report
The offspring produced when pure strains interbreed is described as
Answer Details
The offspring produced when pure strains interbreed is described as a hybrid. When two pure strains with different traits are crossbred, their offspring will inherit a mix of the traits from both parents. These offspring are known as hybrids. Hybridization is commonly used in agriculture to create new varieties of plants or animals with desired traits, such as increased yield, disease resistance, or improved quality. Hybrids can also occur naturally, such as in the case of mules, which are the offspring of a male donkey and a female horse.
Question 24 Report
One of the major criticisms against ‘Mendelian laws is that they do not recognize that
Answer Details
One of the major criticisms against Mendelian laws is that they do not recognize that one trait is often controlled by many pairs of genes. This means that a single trait can be influenced by multiple genes, rather than just one pair of genes as suggested by Mendelian laws. This is known as polygenic inheritance, and it can result in a wide range of possible phenotypes. In some cases, the expression of a trait may also be influenced by environmental factors, further complicating the relationship between genotype and phenotype.
Question 25 Report
Study the genetic cross above showing the inheritance of blood groups from the cross above which of the following F offspring does not
belong to the father?
