WAEC SSCE - Biology - 2000
Pregunta 1 Informe
The neurone that relay the message of effector organs are called
Detalles de la respuesta
The neurons that relay the message of effector organs are called efferent neurons. Efferent neurons are responsible for carrying signals from the central nervous system (brain and spinal cord) to the peripheral nervous system (muscles and glands). They are also referred to as motor neurons because they control muscle movement and other responses to external stimuli. These neurons transmit signals in one direction only, from the central nervous system to the peripheral nervous system, to produce a response or action.
Pregunta 3 Informe
In commensalism
Detalles de la respuesta
Commensalism is a type of symbiotic relationship between two organisms where one organism benefits while the other organism is neither helped nor harmed. This means that the option that best describes commensalism is "one of the organisms gains while the other neither gains nor loses." In commensalism, the organism that benefits is called the commensal, while the organism that is neither helped nor harmed is called the host. The commensal benefits from the association by gaining resources such as shelter, food, or a place to live, while the host is not affected either positively or negatively. Therefore, commensalism is a relationship where one organism gains while the other is unaffected, making it different from other types of symbiotic relationships such as mutualism and parasitism where both organisms can either benefit or one organism gains while the other loses, respectively.
Pregunta 6 Informe
Which of the following organisms is a producer?
Detalles de la respuesta
Spirogyra is a producer. Producers, also known as autotrophs, are organisms that can produce their own food through the process of photosynthesis. Spirogyra is a green algae that contains chloroplasts capable of photosynthesis. Therefore, it is a producer. Mucor, Rhizopus, and yeast are not producers as they are heterotrophic organisms and require external sources of food to survive.
Pregunta 7 Informe
Mammals require a relatively high amount of carbohydrates because
Detalles de la respuesta
Pregunta 8 Informe
During blood transfusion, agglutination could be prevented if a patient having blood group O is given blood
from group
Detalles de la respuesta
During blood transfusion, agglutination can occur if the donor blood group is not compatible with the recipient's blood group. This happens because of the presence of antigens on the surface of red blood cells that can trigger an immune response. Blood group O is considered the universal donor because it lacks the antigens A and B, which means it can be given to individuals with any blood group without causing an immune response. However, a patient with blood group O can only receive blood from a donor with blood group O, as they have antibodies against both antigens A and B, and receiving blood from other groups can cause an immune reaction and agglutination. Therefore, to prevent agglutination, a patient with blood group O should only receive blood from a donor with blood group O.
Pregunta 9 Informe
Which of these has the most complex level of organization?
Detalles de la respuesta
The level of organization refers to the degree of complexity in the structure of an organism. Among the options provided, the heart is the most complex in terms of its level of organization. The heart is a vital organ that pumps blood throughout the body to deliver oxygen and nutrients to cells and remove waste products. It consists of multiple types of tissues such as cardiac muscle, connective tissue, and blood vessels that work together in a coordinated manner to carry out its function. In addition, the heart is also regulated by complex systems such as the nervous system and hormonal system to ensure its proper functioning. In contrast, Euglena and Hydra are both single-celled organisms with simpler structures, and viruses are not even considered living organisms as they do not have cells and cannot carry out life processes on their own. Therefore, the heart, with its complex structure and regulatory mechanisms, has the most complex level of organization among the options provided.
Pregunta 10 Informe
Vitamin C which is water soluble is
Detalles de la respuesta
Vitamin C is a water-soluble vitamin that is also known as ascorbic acid. Water-soluble vitamins are those that dissolve in water and are not stored in the body to a significant degree. This means that any excess amounts of vitamin C are excreted in the urine rather than stored for later use. Therefore, it is important to consume vitamin C regularly through dietary sources such as fruits and vegetables. Vitamin C has several important functions in the body, including acting as an antioxidant to protect cells from damage, supporting the immune system, and aiding in the production of collagen, which is important for healthy skin, bones, and connective tissue. A deficiency in vitamin C can lead to a condition known as scurvy, which causes fatigue, weakness, and skin and gum problems. Cabalamine, pyridoxine, and riboflavin are other B vitamins that are not related to vitamin C.
Pregunta 11 Informe
Which of the following statements is incorrect about diffusion?
Detalles de la respuesta
The statement that is incorrect about diffusion is: "Molecules move from region of lower concentration to that of higher concentration." In diffusion, molecules move from regions of higher concentration to regions of lower concentration until they are evenly distributed. This movement occurs in gaseous, liquid, and solid media, and no membrane is required to effect the movement of molecules. There is no degradation of soluble particles in solvents in the process of diffusion.
Pregunta 12 Informe
Which of the following is not a means of conserving natural resources?
Detalles de la respuesta
The correct answer is "Bush burning" as it is a harmful practice that leads to the destruction of natural resources like forests and soil fertility. Establishment of national parks helps to conserve natural resources like wildlife and their habitats. Selective logging is a practice that involves carefully selecting trees to be cut down, leaving the rest to continue growing and maintaining the ecological balance. Building of dams can help in the conservation of water resources like rivers and lakes, by storing water for later use and controlling floods. On the other hand, bush burning is a harmful practice that leads to the destruction of natural resources like forests, which are home to many animal species and also provide ecological services such as oxygen production and carbon sequestration. It can also lead to soil erosion and loss of soil fertility. Therefore, it is not a means of conserving natural resources, but rather a practice that contributes to their destruction.
Pregunta 13 Informe
Which of the following organisms will not bring about decomposition?
Detalles de la respuesta
Spirogyra is an organism that will not bring about decomposition. Decomposition is a natural process that breaks down dead organisms and organic waste into simpler substances, such as carbon dioxide and water, which can be used by other living organisms. Decomposition is mainly carried out by decomposers, such as bacteria and fungi, that break down the dead matter into smaller compounds. Earthworms, bacteria, and fungi (such as molds) are decomposers that play a significant role in decomposition. However, Spirogyra is a type of algae that does not participate in the process of decomposition. Algae like Spirogyra are producers that produce their own food through photosynthesis and are not involved in breaking down dead organic matter. Therefore, Spirogyra is an organism that will not bring about decomposition, unlike earthworms, bacteria, and molds.
Pregunta 14 Informe
The hydra has two body layers of cells called
Detalles de la respuesta
The two body layers of cells found in a hydra are the ectoderm and endoderm. The ectoderm is the outer layer of cells, while the endoderm is the inner layer of cells. The ectoderm is responsible for protecting the hydra from its environment, while the endoderm is responsible for digestion and nutrient absorption. These two layers work together to allow the hydra to survive and thrive in its aquatic habitat.
Pregunta 16 Informe
Which of the following groups consists of only micro-nutrients?
Detalles de la respuesta
The group that consists of only micro-nutrients is "Manganese, molybdenum and zinc". Micro-nutrients are essential elements required by plants in small quantities for their proper growth and development. Manganese, molybdenum and zinc are all essential micro-nutrients that plants need for various functions such as enzyme activation, photosynthesis, and nitrogen fixation. The other options include at least one macro-nutrient, which is an essential element required in large quantities.
Pregunta 17 Informe
Which of the following conditions will cause a decrease in body temperature?
Detalles de la respuesta
Relaxation of the erector muscles will cause a decrease in body temperature. These muscles are responsible for the raising of body hairs, which traps a layer of insulating air next to the skin. This layer of air helps to reduce heat loss from the body. When the erector muscles relax, the hairs lie flat, and the insulating layer is lost. This leads to an increase in heat loss from the skin to the environment, resulting in a decrease in body temperature.
Pregunta 18 Informe
Character which falls to express itself in the first filial generation but emerges in the second is
Detalles de la respuesta
The character which falls to express itself in the first filial generation but emerges in the second is a recessive trait. This means that the allele for the trait is present in the first generation but is masked by the dominant allele. However, in the second generation, the recessive allele can be expressed if both parents carry the recessive allele and pass it on to their offspring. The classic example of this is seen in Mendelian genetics with the inheritance of pea plant traits, where the wrinkled seed shape is a recessive trait.
Pregunta 19 Informe
Which of the following statements about phosphorous is not correct?
Detalles de la respuesta
The statement that is not correct about phosphorus is: "Helps to regulate the acid-base balance of the body". Phosphorus is an important mineral that is required for many functions in the body, including the formation of bones and teeth, cell growth and repair, and the production of DNA and RNA. It is also involved in regulating the metabolism of proteins, fats, and carbohydrates and is required for many chemical reactions in the body. However, phosphorus does not help to regulate the acid-base balance of the body. That is the role of other minerals such as sodium, potassium, and chloride.
Pregunta 20 Informe
Which of the following parts of the eye is sensitive to light?
Detalles de la respuesta
The part of the eye that is sensitive to light is the retina. The retina is a thin layer of tissue at the back of the eye that contains photoreceptor cells called rods and cones. These cells are responsible for converting light into electrical signals that are transmitted to the brain through the optic nerve, where they are interpreted as visual images. The cornea, choroid layer, and optic nerves do not have the same sensitivity to light as the retina. The cornea is the clear outer covering of the eye that helps to focus incoming light, the choroid layer is a layer of tissue that provides oxygen and nutrients to the retina, and the optic nerves are responsible for transmitting visual information from the retina to the brain.
Pregunta 22 Informe
All the available places on earth which support life constitute the
Detalles de la respuesta
The answer is biosphere. The biosphere refers to all the places on earth where living organisms can exist, which includes the atmosphere, lithosphere (the solid outermost shell of the earth), and hydrosphere (the total amount of water on earth). It is the zone of air, land, and water at the surface of the earth where living organisms are found. The biosphere is the sum of all the ecosystems and includes all the living organisms in the world, their interactions with each other, and with the non-living elements of the environment.
Pregunta 23 Informe
Which of the following statements about nitrogen is not correct? Nitrogen is needed for
Detalles de la respuesta
Pregunta 24 Informe
Which of the following resources is non-renewable?
Detalles de la respuesta
The non-renewable resource is mineral deposits. Mineral deposits refer to natural resources that are found in the earth's crust and have a finite supply that can't be replaced naturally within a short time frame. Once they are extracted and used up, they cannot be regenerated or renewed. Minerals such as coal, oil, and natural gas are examples of non-renewable resources.
Pregunta 25 Informe
Which of the following plant parts does not perform supportive function?
Detalles de la respuesta
Pregunta 26 Informe
Which of the following food substances turns bright red when warmed with suddan III solution?
Detalles de la respuesta
Pregunta 27 Informe
Which of the following best describes a colony of volvox?
Detalles de la respuesta
Pregunta 29 Informe
Which of the following groups consists of heterotrophs?
Detalles de la respuesta
Heterotrophs are organisms that cannot produce their own food and rely on other organisms for their nutrition. They obtain food by consuming other organisms or organic matter. Among the options given, the group that consists of heterotrophs is "Man, Mucor and Mushroom". This is because "Man" refers to humans, which are heterotrophs, and both "Mucor" and "Mushroom" are fungi that are also heterotrophic. The other options include organisms that are either autotrophic (able to produce their own food) or have both autotrophic and heterotrophic modes of nutrition.
Pregunta 30 Informe
Which of the following solutions will induce the condition shown in the diagram?
Detalles de la respuesta
Pregunta 31 Informe
Each neurone consists of the following structures' except
Detalles de la respuesta
The statement is: "Each neurone consists of the following structures except?" The correct answer is "white matter". White matter is not a structure within a neuron. It refers to the tissue composed of nerve fibers (axons) in the central nervous system that are covered in myelin, which gives it a white appearance. A neuron, also known as a nerve cell, consists of three main structures: the cell body, dendrites, and axon. The cell body, or soma, contains the nucleus and other organelles necessary for the neuron to function. Dendrites are short, branching extensions that receive signals from other neurons and transmit them towards the cell body. The axon is a long extension that carries electrical impulses away from the cell body to other neurons or muscles. Therefore, the incorrect statement is "white matter".
Pregunta 32 Informe
The concept of use and disuse of parts was postulated by
Detalles de la respuesta
The concept of use and disuse of parts was postulated by Lamarck. This idea was a key part of Lamarck's theory of evolution, which proposed that organisms could pass on traits that were acquired during their lifetime to their offspring. Lamarck believed that if an organism used a particular body part frequently, it would become stronger and more developed, while disuse would cause the same part to weaken and eventually disappear over time. However, this theory was later disproven by the discovery of genetics and the mechanism of natural selection proposed by Charles Darwin.
Pregunta 33 Informe
The nerves that arise from the brain are known as
Detalles de la respuesta
The nerves that arise from the brain are called cranial nerves. These are a set of twelve paired nerves that emerge directly from the brain and are responsible for transmitting information to and from various parts of the head and neck, including the eyes, ears, nose, tongue, and other areas. Each of the twelve cranial nerves has a specific function, such as controlling eye movements, facial expressions, hearing, and taste perception. They play a vital role in sensory and motor functions, allowing us to perceive the world around us and interact with it.
Pregunta 34 Informe
Parasitism can best be defined as an association between two organisms in which
Detalles de la respuesta
Parasitism is a type of relationship between two organisms in which one organism, called the parasite, benefits from the other organism, called the host, by obtaining nutrients, shelter, or other resources at the expense of the host. The host, in contrast, is harmed by the relationship and may suffer from reduced growth, reproduction, or survival. Therefore, in parasitism, one organism gains (parasite) while the other loses (host).
Pregunta 35 Informe
Trypanosomiasis is associated with
Detalles de la respuesta
Trypanosomiasis, also known as African sleeping sickness, is a disease that is associated with the tsetse fly. The tsetse fly is a blood-sucking insect found in sub-Saharan Africa that can transmit the protozoan parasite Trypanosoma brucei through its bite. When the parasite enters the bloodstream, it causes a variety of symptoms, including fever, headache, joint pain, and fatigue. As the disease progresses, it can also affect the nervous system and lead to sleep disturbances, confusion, and ultimately coma if left untreated. Cockroaches, mosquitoes, and houseflies are not associated with trypanosomiasis, although they can transmit other diseases to humans.
Pregunta 37 Informe
The major reason why foods should be properly covered is that
Detalles de la respuesta
The major reason why foods should be properly covered is to prevent micro-organisms in the air from contaminating the food. Micro-organisms such as bacteria, viruses, and fungi are present in the air and can settle on uncovered food, potentially leading to foodborne illnesses. By properly covering food, we can create a barrier that reduces the risk of these micro-organisms contaminating the food. This is particularly important for perishable foods like meat, dairy, and cooked dishes, which can spoil quickly if not stored properly. While it is true that covering hot foods can help them retain their temperature and prevent them from cooling off too quickly, this is not the primary reason why foods should be covered. Additionally, covering food does not necessarily maintain the taste, as certain flavors can be affected by exposure to air. Finally, covering food does not necessarily affect the evaporation of water, as moisture can escape even when covered depending on the type of covering used.
Pregunta 38 Informe
Which of the following terms is not associated with fingerprint and classification?
Detalles de la respuesta
The term "contour" is not associated with fingerprints and classification. Fingerprint classification is a process used to identify individuals based on the unique characteristics of their fingerprints. These characteristics include patterns such as whorls, arches, and loops, as well as the number and location of ridge characteristics such as bifurcations and ending ridges. Whorls, arches, and loops are the three basic patterns used in fingerprint classification, and each pattern is further classified into subtypes based on the orientation and shape of the ridges. The term "contour" typically refers to the outline or shape of an object, and is not commonly used in the context of fingerprint classification.
Pregunta 39 Informe
Members of the vitamin B complex are
Detalles de la respuesta
Members of the vitamin B complex are water-soluble vitamins. Water-soluble vitamins are those vitamins that dissolve in water and are easily absorbed in the body. They are not stored in large amounts in the body, so excess amounts are eliminated through urine. The B complex vitamins include thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9), and cobalamin (B12). These vitamins play important roles in energy metabolism, nerve function, and DNA synthesis, among other functions. Because they are water-soluble, it is important to consume these vitamins regularly through a balanced diet that includes foods such as whole grains, nuts, seeds, legumes, and leafy green vegetables, as well as fortified cereals and animal products such as meat, fish, and dairy.
Pregunta 40 Informe
The plant cell mostly stores food as
Detalles de la respuesta
Plant cells mostly store food as starch. Starch is a complex carbohydrate made up of many glucose molecules linked together in a branched or unbranched chain. Starch is synthesized in the chloroplasts of photosynthetic cells and stored in specialized organelles called amyloplasts, which are found in roots, tubers, seeds, and other storage organs of the plant. When the plant needs energy, it breaks down the starch into glucose molecules that can be used for cellular respiration.
Pregunta 41 Informe
Which of the labelled structures in the diagram are involved with the entry of carbondioxide for photosynthesis?
Detalles de la respuesta
Pregunta 42 Informe
The following are useful effect of micro-organisms except
Detalles de la respuesta
Microorganisms have many useful effects on human activities, but one of the options listed is not an example of such an effect. Specifically, "decay of meat" is not a useful effect of microorganisms, as it can lead to spoilage and contamination of the meat. In contrast, the other options are all examples of beneficial effects of microorganisms. For example, microorganisms can be used to produce vaccines that help prevent the spread of disease, and they can also be involved in the curing of tobacco and the tanning of leather.
Pregunta 44 Informe
Which of the following best describes the adaptation of the earthworm to its habitat?
Detalles de la respuesta
The adaptation of the earthworm to its habitat is best described by "Living in burrow during the day to prevent desiccation." Earthworms are found in soil, and they need to stay moist to survive because their skin must remain moist for the exchange of gases, like oxygen and carbon dioxide, to occur. They also need to keep their skin moist to prevent desiccation or drying out, which can be fatal. To avoid desiccation during the day, when the sun is shining and the temperature is high, earthworms burrow into the soil, creating a moist and humid environment for themselves. This way, they avoid exposure to the sun and can keep their skin moist, enabling them to breathe and stay hydrated. Therefore, living in burrows during the day to prevent desiccation is a crucial adaptation of earthworms to their habitat, which enables them to survive in soil environments. The other options listed do not describe adaptations that earthworms possess to survive in their habitat.
Pregunta 45 Informe
Vitamin C deficiency results in
Detalles de la respuesta
Vitamin C deficiency results in scurvy. Scurvy is a disease that can occur when a person does not consume enough vitamin C, which is also known as ascorbic acid. Vitamin C is important for the production of collagen, which is a protein that helps to hold cells together in the body. When a person does not get enough vitamin C, their body cannot produce enough collagen, which can lead to symptoms such as fatigue, weakness, joint pain, and bleeding gums. In severe cases, scurvy can also cause open sores on the skin and even death. To prevent scurvy, it is important to consume foods that are rich in vitamin C, such as citrus fruits, strawberries, kiwi, and broccoli.
Pregunta 46 Informe
The unit contained in a cell structure responsible for changes in form and shape of organisms is called
Detalles de la respuesta
Pregunta 47 Informe
Which of the following organisms has the largest surface area-to-volume ratio?
Detalles de la respuesta
Amoeba has the largest surface area-to-volume ratio among the organisms listed. This is because amoebas are unicellular organisms with a relatively large surface area compared to their volume. Since their shape is irregular and constantly changing, they can increase their surface area by extending and retracting pseudopodia. This allows them to take in nutrients and oxygen from their environment and expel waste products more efficiently. In contrast, larger organisms such as man, earthworm, and grasshopper have much smaller surface area-to-volume ratios due to their larger sizes and more complex body structures. Therefore, the correct answer to the question is Amoeba.
Pregunta 48 Informe
The presence of a large member of mitochondria in a cell indicates that
Detalles de la respuesta
The presence of a large number of mitochondria in a cell indicates that the cell is very active. Mitochondria are organelles in cells responsible for producing energy through respiration. The more mitochondria a cell has, the more energy it can produce. Therefore, cells with high energy demands, such as muscle cells, have a higher number of mitochondria compared to cells with lower energy demands, such as skin cells. So, the presence of a large number of mitochondria in a cell is an indicator of its high activity level.
Pregunta 50 Informe
The following are the functions of supporting tissues in plant except
Detalles de la respuesta
Supporting tissues in plants are those tissues that provide mechanical support to the plant body. They include collenchyma, sclerenchyma, and xylem. Out of the options provided, the function of supporting tissues that is not correct is "secretory." Supporting tissues do not have a secretory function, as that role is typically carried out by specialized cells or tissues such as glands or trichomes.
Pregunta 51 Informe
A very poor growth in plants and discolouration of leaves signifies the deficiency of
Detalles de la respuesta
Pregunta 52 Informe
What happens to an ovule of a flower, after fertilization? It
Detalles de la respuesta
After fertilization, the ovule of a flower develops into a seed. The fertilized ovule undergoes changes and forms the embryo which later develops into a new plant. The ovary of the flower also enlarges and becomes the fruit that encloses the seed. Thus, the correct option is "becomes a seed."
Pregunta 53 Informe
Which of the following represents Mendel’s second law of inheritance? The factors for two pairs of contrasting
characters are
Detalles de la respuesta
The statement that represents Mendel's second law of inheritance is "inherited independently of each other." Mendel's second law of inheritance, also known as the law of independent assortment, states that different traits, or factors, are inherited independently of each other. This means that the inheritance of one trait does not influence the inheritance of another trait. Mendel discovered this law by studying pea plants and observing that the inheritance of seed color was independent of the inheritance of seed texture. He found that the factors for these two traits were located on different chromosomes and inherited independently of each other. Therefore, the option "inherited independently of each other" represents Mendel's second law of inheritance, which states that traits are inherited independently and do not influence each other's inheritance. The other options listed do not represent Mendel's second law of inheritance.
Pregunta 54 Informe
Which of the following is responsible for the increased heart beat of a boy who saw a python? increased
production of
Detalles de la respuesta
The increased heart rate of a boy who saw a python is due to the production of adrenaline. Adrenaline is a hormone released by the adrenal gland in response to stress, fear or danger. It prepares the body for a "fight or flight" response, which involves increased heart rate, blood pressure, and breathing rate, as well as the release of glucose from energy stores in the body. These physiological changes help the body to deal with a perceived threat or danger. In this case, the boy's body is preparing to either fight the python or flee from it, and the release of adrenaline is helping to facilitate this response.
Pregunta 55 Informe
Which of the following is not released during decay of living matter?
Detalles de la respuesta
Oxygen is not released during decay of living matter. During the process of decay, microorganisms break down complex organic compounds into simpler substances. In the absence of oxygen, this process is called anaerobic decay, and the end products include methane and carbon dioxide. In the presence of oxygen, the process is called aerobic decay, and the end products include carbon dioxide, water, and heat energy. However, oxygen itself is not released during the decay process.
Pregunta 56 Informe
The abiotic factor which determines the depth to which light penetrates in a pond is
Detalles de la respuesta
The abiotic factor that determines the depth to which light penetrates in a pond is turbidity. Turbidity is the measurement of the amount of suspended particles in water, such as soil, silt, and plankton. These particles can absorb or scatter light, which reduces the amount of light that penetrates the water. The more suspended particles present in the water, the more turbid the water becomes, and the less light can penetrate the water. In a pond, the depth to which light can penetrate affects the growth of aquatic plants and algae. These photosynthetic organisms require sunlight to produce food, and the depth to which light can penetrate affects the amount of light available for photosynthesis. Therefore, the abiotic factor that determines the depth to which light penetrates in a pond is turbidity, which is the amount of suspended particles in water that absorb or scatter light. The other options listed do not determine the depth to which light penetrates in a pond.
Pregunta 57 Informe
Which of the following structures is not present in the vascular bundles of a dicot stem?
Detalles de la respuesta
Pregunta 58 Informe
Which of the labelled structures in the diagram will shrink when plasmolysis occurs?
Detalles de la respuesta
Pregunta 59 Informe
The simplest form of nervous pathway which links receptors with effectors is known as the
Detalles de la respuesta
The simplest form of nervous pathway which links receptors with effectors is known as the reflex arc. The reflex arc is responsible for reflex actions, which are automatic, involuntary responses to a particular stimulus. When a stimulus is detected by sensory receptors, the impulse travels along sensory nerves to the spinal cord, where it is processed by a small group of neurons called the reflex center. From there, the impulse travels along motor nerves to the effector muscles, which respond by contracting or relaxing. The reflex arc is a rapid and efficient way of responding to potentially harmful or dangerous stimuli without involving the conscious brain. Examples of reflex actions include pulling your hand away from a hot stove, blinking when an object comes close to your eye, or sneezing when dust irritates your nose.
Pregunta 60 Informe
In which of the following organisms is ammonia excreted as a waste product?
Detalles de la respuesta
Ammonia is a highly toxic substance that needs to be eliminated from the body as soon as possible. In some organisms, ammonia is excreted directly as a waste product, while in others, it is converted into less toxic substances before excretion. Among the given options, Amoeba is an organism that excretes ammonia as a waste product. Amoeba is a unicellular organism that lives in water and has a simple structure. It does not have specialized excretory organs like kidneys, so it excretes metabolic waste directly through its cell membrane by diffusion. Since ammonia is highly soluble in water, it can diffuse out of the cell easily, making ammonia the primary excretory product of Amoeba. In contrast, humans, birds, and Spirogyra excrete urea or uric acid, which are less toxic and more water-conserving than ammonia.
Pregunta 61 Informe
TEST OF PRACTICAL KNOWLEDGE QUESTION
1 (a) (i) identify specimens A and B without reasons (ii) Give four differences between specimens A and B .
Using a sharp knife, scalpel or blade, cut specimen B into two equal halves to expose the internal structures.
b. (i) Make a labeled drawing of 8 cm to 10cm long to show the observable internal structures of specimen B.
(ii) State the dispersal mechanism of specimen B.
(C)(i) Identify C, D and E without reasons. (ii) State two features, each of specimen C, D and E which adapt to their habitats.
2. The height (cm) of 20 students in a class are as follows:.155, 157, 151 169, 162, 151, 149, 165, 169,176.169, 179,173, 179, 173, 169, 157, 155, 165, 157, 197 and 162.
Use them to answer the following questions:
(a) Make a frequency distribution table of class interval of five of the different heights (b) what is the modal height? (ii) median height? (ii) mean height?
(c) (i) Construct a histogram showing the variation of height, amongst the students with the heights on the horizontal number of students on the vertical axis.
(ii) How many students fall into each or the height axis and number of students on the vertical axis.
(iii) How many students have height between 155 and 179?
(iv) Find the difference in height between shortest and the tallest students.
(d) (i)What type of variation is height? (ii) Mention three other examples of the type of variation in (d) (i) above.
3.(a) identify specimen F, G, H, I, J, and K without reasons. (b)(i) State one observable feature by which each of specimens F,G and H obtain their food.
(ii) State three observable features which contribute to the survival of specimen I.
(c)Mention two observable characteristics each, of specimens J and K. (ii) Name the two bones, each, which articulates with specimens J and K
(iii) Make a labeled drawing of 8cm to 10 cm long of specimens K.
None
Detalles de la respuesta
None
Pregunta 62 Informe
(a) Describe the water cycle using an annotated diagram (s) only.
(b) What is the importance of water tc living organisms?
None
Detalles de la respuesta
None
Pregunta 63 Informe
(a) State five different methods used in vegetative propagation in plants giving an example in each case.
State five (i) advantages and (ii) disadvantages of vegetative propagation.
None
Detalles de la respuesta
None
Pregunta 64 Informe
(a) Name the four levels of organisation in living organisms.
(ii) Explain two of the levels of organisation named in (a)(i) above
Detalles de la respuesta
None
Pregunta 65 Informe
(a) List five classes of food other than carbohydrates.
(b) Explain why glucose is taken by an athlete ready for a race rather than corn meal.
(c) Describe the test for starch.
None
Detalles de la respuesta
None
Pregunta 66 Informe
(a) Explain the term osmosis.
(b) Describe an experiment to show that the xylem tissue conducts water from the rot to the shoot.
(c)(i) Explain what happens to a red blood cell when placed in a hypotonic solution
(ii) Mention three conditions that may cause haemolysis
Detalles de la respuesta
None
