WAEC SSCE - Biology - 2011
Pregunta 1 Informe
If Amoeba is placed in a salt solution. the contractile vacuoles would
Detalles de la respuesta
When an amoeba is placed in a salt solution, the salt solution is hypertonic (higher concentration of solute) compared to the cytoplasm of the amoeba. As a result, water from the cytoplasm moves out of the cell through osmosis to the hypertonic salt solution, causing the amoeba to shrink. In response to this, the contractile vacuole in the amoeba would form more frequently to pump out the excess water from the cytoplasm in order to maintain the osmotic balance and prevent the amoeba from bursting. Therefore, the correct option is "be formed less frequently" as the opposite is true.
Pregunta 2 Informe
Which of the following cells are not regarded as specialized?
Detalles de la respuesta
Somatic cells are not regarded as specialized cells. Somatic cells are the body cells that make up most of the body tissues and organs. They perform general functions in the body such as providing structural support, protection, and nutrient transport. In contrast, specialized cells have specific functions and characteristics that allow them to perform specific tasks. For example, sperm cells are specialized cells that are involved in reproduction, muscle cells are specialized cells that are involved in movement, and root hair cells are specialized cells that are involved in nutrient uptake.
Pregunta 3 Informe
Which of the following statements best describes haemoglobin? It is
Detalles de la respuesta
Haemoglobin is an oxygen-carrying pigment found in the red blood cells of mammals. It is responsible for transporting oxygen from the lungs to other tissues in the body, and it also helps to transport carbon dioxide from the tissues back to the lungs for exhalation. Therefore, the statement that best describes haemoglobin is that it is an oxygen-carrying pigment.
Pregunta 4 Informe
Inhaled air is made warm and moist in the
Detalles de la respuesta
Inhaled air is made warm and moist in the nasal cavity. The nasal cavity contains specialized structures called turbinates, which help to increase the surface area of the nasal cavity. As air passes through the nasal cavity, it comes into contact with the moist mucous membranes lining the cavity, which help to humidify the air and also trap any dust or particles in the air. Blood vessels in the mucous membranes also warm the air, bringing it closer to body temperature. Overall, the nasal cavity helps to prepare inhaled air for entry into the lungs, making it more suitable for respiration.
Pregunta 5 Informe
Which of the following structures produces the greatest variety of digestive enzymes?
Detalles de la respuesta
The structure that produces the greatest variety of digestive enzymes is the pancreas. The pancreas is an organ located behind the stomach and it secretes digestive enzymes that help in the breakdown of carbohydrates, fats, and proteins in the small intestine. The enzymes produced by the pancreas include amylase, lipase, and protease, which can break down carbohydrates, fats, and proteins respectively. The salivary glands produce amylase which helps in the breakdown of carbohydrates in the mouth, while the stomach produces pepsin, which breaks down proteins. The colon, on the other hand, absorbs water and electrolytes, and is not primarily involved in enzyme production. Therefore, the correct answer is the pancreas.
Pregunta 6 Informe
In which of the following habitats is Paramecium no found
Detalles de la respuesta
Pregunta 7 Informe
Which of the following components of Larmark’s theory of evolution is considered faulty?
Detalles de la respuesta
The component of Lamarck's theory of evolution that is considered faulty is "Changes that result in individuals of the same species are transmitted to offspring." This idea, also known as the inheritance of acquired characteristics, suggests that an organism can pass on characteristics it has acquired during its lifetime to its offspring. However, this has been disproven by modern genetics, which shows that inherited traits are determined by an organism's DNA and not influenced by its experiences during life. Therefore, traits acquired during an individual's lifetime cannot be inherited by its offspring.
Pregunta 9 Informe
Which of the following enzymes is active in the duodenum?
Detalles de la respuesta
The enzyme that is active in the duodenum is Trypsin. When food leaves the stomach, it enters the duodenum of the small intestine. Trypsin is produced by the pancreas and is released into the duodenum. Its function is to break down proteins into smaller peptides. This process aids in digestion and allows for the absorption of essential amino acids by the body. Therefore, the correct option is Trypsin.
Pregunta 10 Informe
Which of the following statements is not true about continuous variation? It
Detalles de la respuesta
The statement that is not true about continuous variation is: "is usually controlled by one or two pair(s) of genes". Continuous variation is a type of variation that shows a wide range of possible values for a particular trait, and is usually controlled by several genes, with each gene contributing a small amount to the final phenotype. Continuous variation can also be influenced by environmental factors, such as nutrition or exposure to certain chemicals. The distribution of continuous variation usually follows a normal distribution curve, with most individuals clustering around the mean value and fewer individuals at the extremes of the distribution. Therefore, the statement that is not true is that continuous variation is usually controlled by one or two pair(s) of genes.
Pregunta 11 Informe
Vaccination results in
Detalles de la respuesta
Vaccination results in the production of antibodies which destroy toxins of germs. When a vaccine is introduced into the body, it triggers an immune response, causing the immune system to produce specific antibodies against the pathogen. These antibodies circulate in the body and are ready to attack the pathogen if it enters the body. In this way, the body is able to quickly and effectively fight off the pathogen and prevent the development of the disease. This is the primary mechanism by which vaccination protects against infectious diseases.
Pregunta 12 Informe
A man with blood group It IA IA is married to a woman with blood group IA IO. The blood group of their son is likely to be
Detalles de la respuesta
The man has blood group IA IA, which means that he has two copies of the A allele. The woman has blood group IA IO, which means she has one A allele and one O allele. When they have a child, each parent passes one allele to their child. The possible combinations of alleles that their child can inherit are IA from the father and IA or IO from the mother. So, the child can have blood group IA IA, IA IO, or IO IO. However, the child cannot have blood group B or AB because neither parent has the B allele. Therefore, the likely blood group of their son is A.
Pregunta 14 Informe
Differences in characteristics observed between individuals of the same species is known as
Detalles de la respuesta
The term used to describe differences in characteristics observed between individuals of the same species is "variation". Variation can be caused by a number of factors, including genetic differences, environmental factors, and interactions between genes and the environment. Variation can be observed in many different traits or characteristics, such as height, weight, color, behavior, and more. Understanding and studying variation is important in fields such as genetics, ecology, and evolution, as it can help us to understand how and why populations change over time.
Pregunta 15 Informe
The following are abiotic components of an ecosystem except
Detalles de la respuesta
The answer is "bacteria". Bacteria are living organisms and are part of the biotic components of an ecosystem. The other options, temperature, oxygen, and soil, are abiotic components of an ecosystem. Abiotic factors are non-living components of an ecosystem that can affect the growth and survival of living organisms. Temperature affects the rate of biological processes, oxygen is necessary for respiration, and soil provides nutrients and support for plants.
Pregunta 17 Informe
The process whereby electrons are emitted from chlorophyll and returned to it unchanged is known as?
Detalles de la respuesta
The process whereby electrons are emitted from chlorophyll and returned to it unchanged is known as cyclic photophosphorylation. During this process, light energy is absorbed by chlorophyll and used to excite electrons, which then move along an electron transport chain and ultimately return to the chlorophyll molecule. This results in the generation of ATP (adenosine triphosphate), which is an important energy source for the cell. Unlike non-cyclic photophosphorylation, which involves the transfer of electrons to an electron acceptor and the subsequent generation of NADPH in addition to ATP, cyclic photophosphorylation only generates ATP.
Pregunta 18 Informe
The branch of Biology that deals with the principles of classification of organisms is known as
Detalles de la respuesta
The branch of biology that deals with the principles of classification of organisms is known as taxonomy. Taxonomy is the scientific study of how living things are classified or grouped based on their characteristics and relationships with one another. This involves identifying, naming, and organizing species into hierarchical categories or taxonomic ranks, such as kingdom, phylum, class, order, family, genus, and species. The aim of taxonomy is to provide a systematic and logical framework for the study of biodiversity and the relationships among different organisms.
Pregunta 19 Informe
Which of the following statements about photosynthesis is not true?
Detalles de la respuesta
The statement that is not true about photosynthesis is "Plants can photosynthesize without an increase in dry weight." Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in organic compounds such as sugars. This process occurs in specialized organelles called chloroplasts, which are found in the cells of the plant's leaves, stems, and sometimes roots. During photosynthesis, carbon dioxide and water are converted into glucose and oxygen, with the help of chlorophyll and other pigments that absorb light energy. The oxygen produced during photosynthesis comes from the splitting of water molecules, not the breakdown of water. And, photosynthesis does lead to an increase in dry weight, as the plant stores the energy in the form of organic compounds.
Pregunta 20 Informe
Which of the following pairs of cells carry out the same function?
Detalles de la respuesta
Pregunta 21 Informe
Cells that utilise a lot of energy are characterized by the presence of a large number of
Detalles de la respuesta
Cells that utilize a lot of energy require a lot of ATP, the energy currency of cells. Mitochondria are the organelles responsible for producing ATP in cells through cellular respiration. Therefore, cells that use a lot of energy, such as muscle cells or neurons, will have a large number of mitochondria to produce the ATP they require. So, the correct answer is mitochondria.
Pregunta 22 Informe
If a person has two alleles of the sickle cell anaemia gene, the person
Detalles de la respuesta
If a person has two alleles of the sickle cell anaemia gene, the person has the disease. Sickle cell anaemia is an autosomal recessive genetic disorder, which means that two copies of the abnormal gene are required to have the disease. A person with one abnormal and one normal gene is a carrier and does not have the disease but can pass the abnormal gene to their offspring. A person with two abnormal genes has the disease and may experience symptoms such as pain, fatigue, and anemia.
Pregunta 23 Informe
Which of the following structures is not involve in respiration?
Detalles de la respuesta
The structure that is not involved in respiration is the stomach. Respiration is the process of gas exchange, which involves taking in oxygen and releasing carbon dioxide. The lungs, mouth, and trachea are all involved in respiration. The lungs are the primary organ of respiration where gas exchange occurs. The trachea, also known as the windpipe, is the tube that carries air from the mouth and nose to the lungs. The mouth serves as an opening for air to enter the respiratory system. The stomach, on the other hand, is involved in the digestion of food, which is a separate process from respiration.
Pregunta 24 Informe
Which of the following statements best describes protein synthesis?
Detalles de la respuesta
Pregunta 25 Informe
Which of the following methods is appropriate for the cultivation of cassava?
Detalles de la respuesta
The appropriate method for the cultivation of cassava is stem cutting. This involves cutting stems of cassava plants into sections, usually 20-30 cm long, and planting them in soil. The stems will sprout and grow into new cassava plants. This method is commonly used because cassava does not produce true seeds and cannot be propagated through budding or fragmentation. Root cutting can be used, but it is less efficient than stem cutting because it takes longer for the roots to develop into new plants.
Pregunta 26 Informe
The conversion of glucose to starch in the leaf during the day principally
Detalles de la respuesta
During photosynthesis, plants produce glucose as a result of the conversion of carbon dioxide and water using sunlight. This glucose can be used to meet the energy requirements of the plant. However, since the plant can only use so much glucose at once, it needs to store the excess glucose for future use. The conversion of glucose to starch in the leaf during the day primarily enables the leaf to store the excess glucose as starch. Starch is a more compact and stable form of glucose storage, which is easily stored in the plant cells. By converting glucose to starch, the plant can store more glucose in a smaller space and keep it stable for longer periods. Thus, the conversion of glucose to starch in the leaf is an essential process that enables plants to store excess glucose and meet their energy needs efficiently.
Pregunta 27 Informe
Use the information on capture-recapture method to calculate the total number of organisms in a habitat.
First capture = 200
Second capture = 120
Number of organisms with mark in second capture = 40
The total number of organisms therefore is
Detalles de la respuesta
The capture-recapture method is used to estimate the total population size of a species in a given area. The formula for this method is: Total population size = (number marked in first sample * number in second sample) / number marked in second sample Using the values given in the question: Number marked in first sample = 200 Number in second sample = 120 Number marked in second sample = 40 Plugging in these values into the formula, we get: Total population size = (200 * 120) / 40 = 600 Therefore, the total number of organisms in the habitat is 600. So the answer is option C - 600.
Pregunta 28 Informe
The rate of decomposition of organisms is faster in the tropical rain forest than in other biomes because
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Pregunta 29 Informe
What will be the chromosome number of the hybrid of two varieties of a plant with 36 chromosomes in the endosperm cell?
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Pregunta 30 Informe
Leguminous crops are incorporated into crop rotation in order to
Detalles de la respuesta
Leguminous crops are incorporated into crop rotation in order to promote nitrogen fixation. Leguminous plants form a symbiotic relationship with nitrogen-fixing bacteria, Rhizobia, which live in nodules on their roots. These bacteria convert atmospheric nitrogen into a form that plants can use, such as ammonia or nitrates. When leguminous crops are grown and then plowed under the soil, the nitrogen-rich plant material breaks down and releases this essential nutrient into the soil, making it available for other crops to use in subsequent rotations. Therefore, leguminous crops are important in maintaining soil fertility, reducing the need for synthetic fertilizers, and increasing crop yields.
Pregunta 31 Informe
Kreb’s cycle occurs in the
Detalles de la respuesta
Kreb's cycle, also known as the citric acid cycle or TCA cycle, occurs in the mitochondria. It is a series of chemical reactions that occur in the presence of oxygen and play a critical role in the production of energy in the form of ATP during cellular respiration. The cycle starts with the entry of acetyl-CoA into the cycle, which then undergoes a series of reactions to produce NADH and FADH2, which are important electron carriers. These electron carriers then go on to participate in the electron transport chain, leading to the production of ATP.
Pregunta 32 Informe
A vestigial structure in humans is
Detalles de la respuesta
A vestigial structure in humans is a structure that has lost its original function due to evolution. In other words, it served a purpose in an ancestor of the species, but is no longer necessary or useful in the current form of the species. In humans, the tail bone or coccyx is considered a vestigial structure because it was used for balance and mobility in our primate ancestors, but has no apparent function in humans.
Pregunta 33 Informe
Assuming that a period of stable population size is followed by a period when natality increases by ten (1O) per cent and immigration increases by twenty (20) percent of population size. The population size will
Detalles de la respuesta
If the population size is stable, it means that the birth rate (natality) and immigration rate are equal to the death rate (mortality) and emigration rate respectively. However, if there is a ten percent increase in natality and a twenty percent increase in immigration, the population size will begin to increase. This is because the number of individuals added to the population through births and immigration will exceed the number lost through deaths and emigration, resulting in a net increase in population size. Therefore, the correct answer is "begin to increase."
Pregunta 34 Informe
A monocot root IS different from a dicot root by having
Detalles de la respuesta
Pregunta 35 Informe
The testes in male mammals descend into the scrotal sac because
Detalles de la respuesta
The testes are the male reproductive organs responsible for producing sperm and the male hormone testosterone. In mammals, including humans, the testes initially form inside the abdomen, near the kidneys. However, for the production of healthy sperm, the testes need to be maintained at a temperature lower than the normal body temperature. Hence, during fetal development, a structure called the gubernaculum begins to pull the testes down towards the scrotal sac. As the testes move down, they are accompanied by blood vessels, nerves, and a duct called the vas deferens, which carry sperm from the testes to the urethra. Once the testes reach the scrotal sac, they are positioned outside the body, where the temperature is lower than the body temperature. This helps to keep the testes cool, which is important for the production of healthy sperm. Therefore, the testes in male mammals descend into the scrotal sac to maintain a relatively low temperature that is optimal for the production of healthy sperm.
Pregunta 36 Informe
Which of the following substances when lost from the body of a mammal will not be returned to the ecosystem?
Detalles de la respuesta
Pregunta 37 Informe
Adenine pairs with thymine because
Detalles de la respuesta
Adenine pairs with thymine because one is a purine base (adenine) and the other is a pyrimidine base (thymine). The structure of DNA requires that the nitrogenous bases, which make up the "rungs" of the DNA ladder, pair in a specific way: purines (adenine and guanine) must pair with pyrimidines (thymine and cytosine). Adenine has a complementary hydrogen-bonding pattern with thymine, which allows them to pair together, forming two hydrogen bonds between them. This specific pairing between the bases is important for DNA replication and the accurate transmission of genetic information.
Pregunta 38 Informe
A sample of wet garden soil of known weigh was heated to constant weight. The loss of weight is due to loss of
Detalles de la respuesta
Pregunta 39 Informe
A purple colour was obtained when sodium hydroxide solution and a drop of copper sulphate solution were added to a food substance. The food substance is likely to be a
Detalles de la respuesta
The food substance is likely to be a protein. When sodium hydroxide solution and a drop of copper sulphate solution are added to a protein, it forms a violet or purple color. This is due to the formation of a complex between the copper ions and the peptide bonds in the protein molecules. The intensity of the color depends on the concentration of the protein in the solution.
Pregunta 40 Informe
During sexual reproduction in Paramecium, how many times does the zygote divide to produce eight nuclei?
Detalles de la respuesta
During sexual reproduction in Paramecium, the zygote undergoes meiosis to form four haploid nuclei. These haploid nuclei then undergo two rounds of mitosis to produce eight nuclei. Therefore, the zygote divides three times to produce eight nuclei. The correct answer is 3.
Pregunta 41 Informe
Which of the following neurons may not have myelin sheath?
Detalles de la respuesta
Sensory neurons may not have myelin sheath. Sensory neurons are responsible for transmitting signals from the sensory receptors (such as those in the skin, eyes, ears, nose, and tongue) to the central nervous system (brain and spinal cord). Some sensory neurons have long axons that extend from the periphery to the spinal cord or brain, and these axons may be covered by myelin sheath produced by Schwann cells. However, not all sensory neurons have myelin sheath. For example, some sensory neurons that are involved in transmitting pain signals may have very short or no myelin sheath. This lack of myelin sheath can contribute to the sensation of pain, as it allows the signal to be transmitted more slowly and with greater intensity.
Pregunta 42 Informe
Which of the following groups of substances are not six-carbon compounds?
Detalles de la respuesta
The correct answer is "Pyruvate and cellulose" because both pyruvate and cellulose are not six-carbon compounds. Pyruvate is a three-carbon compound produced during glycolysis, while cellulose is a polymer made up of repeating glucose units and has a much larger molecular weight than glucose. The other options contain at least one six-carbon compound: glucose has six carbons, lactose is made up of glucose and galactose (both six-carbon compounds), and cellulose contains repeating glucose units.
Pregunta 43 Informe
A xerophyte conserves water by possession of the following features except
Detalles de la respuesta
A xerophyte is a plant that has adapted to survive in environments with low water availability. To conserve water, xerophytes possess certain features such as a thick cuticle on leaves, sunken stomata to reduce water loss, and a fleshy stem to store water. However, xerophytes do not have broad leaves as this would result in increased transpiration and water loss, which is contrary to their water-conserving adaptation. Therefore, the correct answer is "broad leaves".
Pregunta 44 Informe
The falling off of leaves of deciduous trees is helpful to the plant because it
Detalles de la respuesta
The falling off of leaves of deciduous trees is helpful to the plant because it reduces the rate of transpiration. Deciduous trees shed their leaves during the dry season to conserve water. The leaves of these trees have stomata that can lose water through transpiration. Shedding of leaves helps reduce the surface area of the plant that can lose water through transpiration, thus conserving water. Additionally, the fallen leaves decompose, adding nutrients to the soil, which are later used by the plant to produce new leaves.
Pregunta 45 Informe
Secondary growth is brought about by the activities of the
Detalles de la respuesta
Secondary growth in plants refers to the increase in the girth or thickness of the plant stem or root. This process is brought about by the activity of the vascular cambium, a lateral meristem responsible for the production of secondary xylem and phloem. The vascular cambium divides actively, producing new cells towards the inner side (secondary xylem) and the outer side (secondary phloem). As a result, the stem or root increases in girth over time. The other options, phellogen and phelloderm, are involved in the formation of the protective outer bark in woody plants.
Pregunta 46 Informe
Filtrate in the Bowman’s capsule contains vitamins because
Detalles de la respuesta
Filtrate in the Bowman's capsule contains vitamins because they have a low molecular weight. Vitamins are organic compounds that the body needs in small amounts to maintain normal physiological function. Due to their small size and molecular weight, they can easily pass through the glomerulus and into the Bowman's capsule during filtration in the kidney. Once in the filtrate, vitamins can be reabsorbed into the bloodstream and utilized by the body, or excreted in the urine if they are present in excess. Therefore, the correct option is "they have low molecular weight".
Pregunta 47 Informe
Ecological investigation in a habitat includes the following procedures except
Detalles de la respuesta
Ecological investigation in a habitat includes choosing a habitat, identification of specimens, and measuring abiotic and biotic factors. Determining the genetic makeup of specimens is not typically included as part of ecological investigation in a habitat. Genetic makeup is more relevant in genetic research or population genetics, which is a different field of study from ecology. Ecological investigation is focused on the study of the relationships and interactions between living organisms and their environment. This involves examining the physical and chemical factors of the environment, as well as the diversity and distribution of species in the ecosystem.
Pregunta 48 Informe
Which of the following activities promotes forest conservation?
Detalles de la respuesta
Afforestation is an activity that promotes forest conservation. Afforestation involves the planting of new trees in areas where there was no forest before. This activity helps to increase the forest cover, which provides a habitat for many species of animals and plants, helps to reduce soil erosion, and prevents flooding. Additionally, afforestation helps to combat climate change by absorbing carbon dioxide from the atmosphere. Therefore, afforestation is an important activity that promotes the conservation of forests. The other options listed in the question, such as lumbering, use of firewood for cooking, and production of paper, can contribute to deforestation and degradation of forests.
Pregunta 49 Informe
The following processes are involved in water movement in the endodermis except
Detalles de la respuesta
The correct answer is option C: diffusion. Water movement in the endodermis of plant roots is regulated by a specialized cell layer known as the Casparian strip. The Casparian strip prevents water and solutes from moving freely through the cell walls between endodermal cells, forcing them instead to cross the plasma membrane of the endodermal cells. Once inside the endodermal cells, water and solutes can move through two pathways: the apoplastic pathway, which is the space between the cell walls of adjacent cells, and the symplastic pathway, which is the cytoplasmic continuum that links adjacent cells through plasmodesmata. Water moves through the symplastic pathway by osmosis, driven by differences in solute concentration between the soil and the root. Active transport of solutes also plays a role in establishing these concentration gradients. Once inside the root, water and solutes can be transported to the xylem, which carries them to the rest of the plant. The process that is not involved in water movement in the endodermis is diffusion, which is the movement of solutes from an area of high concentration to an area of low concentration. While diffusion can occur in the apoplastic and symplastic pathways, it is not the primary driving force behind water movement through the endodermis.
Pregunta 51 Informe
Which of the following methods does not make water fit for drinking?
Detalles de la respuesta
Pregunta 53 Informe
The following organisms are producers except
Detalles de la respuesta
Hibiscus and Spirogyra are plants that are capable of producing their own food through photosynthesis. Cactus is also a plant that is capable of producing food, although it uses a specialized form of photosynthesis called CAM photosynthesis. On the other hand, Mushroom is not a plant and is not capable of producing its own food. It is a fungus that obtains its nutrients by decomposing organic matter. Therefore, Mushroom is the organism in the given options that is not a producer.
Pregunta 54 Informe
Which of the following is an effector organ?
Detalles de la respuesta
Effector organs are the organs that carry out the response or action in response to a stimulus. Among the given options, the skin is an effector organ as it responds to stimuli such as heat, cold, pressure, and pain, by activating various physiological mechanisms such as sweating, shivering, and blood vessel constriction or dilation, to maintain the body's internal balance or homeostasis. The tongue, nose bridge, and ear glands are not considered effector organs as they do not have a direct role in carrying out a physiological response to a stimulus.
Pregunta 55 Informe
What is the probability? of a man of blood group AB married to a woman of blood group O producing a child of blood group O?
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Pregunta 56 Informe
Some animals return to water bodies to reproduce because
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Pregunta 57 Informe
ore sweat is produced during muscular exercise because
Detalles de la respuesta
More sweat is produced during muscular exercise because the temperature of the body rises. When muscles contract during exercise, they generate heat which raises the body temperature. To prevent the body from overheating, sweat glands are stimulated to produce sweat. Sweat, which is mostly composed of water and salt, evaporates from the skin surface and removes heat from the body, thus reducing the body temperature. This process is known as evaporative cooling. Therefore, the more a person exercises, the more heat is produced, and the more sweat is produced to cool the body down.
Pregunta 58 Informe
Which of the following practices improves crop yield in a clayey soil? Addition of
Detalles de la respuesta
The practice that improves crop yield in a clayey soil is the addition of lime and humus. Clayey soils are often compact and have low nutrient levels, making it difficult for crops to grow properly. The addition of lime helps to reduce the acidity of the soil, which can be toxic to plants. The addition of humus helps to increase the organic matter content of the soil, which can improve soil structure and nutrient availability. Both lime and humus can help to improve soil fertility, making it easier for crops to grow and produce a higher yield.
Pregunta 59 Informe
The removal of all the phloem tissues of the stem of a plant close to the root system for a long period of time is likely to
Detalles de la respuesta
Phloem is responsible for the transportation of the products of photosynthesis, including sugar and other nutrients from the leaves to other parts of the plant, including the roots. If all the phloem tissues of the stem of a plant close to the root system are removed for a long period of time, the roots will not receive the necessary nutrients to survive. Without the products of photosynthesis, the roots will not have enough energy to carry out important processes such as respiration and growth. Therefore, the most likely outcome of this scenario is that the plant will wither and eventually die.
Pregunta 60 Informe
(a)State the second law of thermodynamics.
(ii) Use the second law of thermodynamics to explain the flow of energy across different trophic levels in a food chain.
(b) (I) State three factors that can likely limit the size of human populations.
(ii) Outline two ways each by which humans can overcome the factors named in (b)(i).
Detalles de la respuesta
None
Pregunta 61 Informe
(a) Explain the following terms:
(i) putrefaction
(ii) nitrogen fixation
(iii) nitrification
(iv) denitrification
(b) State three differences between nitrogen fixation and denitrification.
(c) Explain how nitrogen from urine gets to the roots of plants. W
None
Detalles de la respuesta
None
Pregunta 62 Informe
TEST OF PRACTICAL KNOWLEDGE QUESTION
(a) Study carefully specimens A, B, C, and D. copy and complete the table below
| Specimen | Part modified to form specimen | Mode of propagation | Stored material |
| A | |||
| B | |||
| C | |||
| D |
(b) In a tabular form state four observable differences between specimens A and C.
(c) Crush a small portion of specimen D and divide it into three equal parts. (i) Place a portion on a white tile and add two (2) drops of iodine solution.
(ii) Place another portion in a test tube and add one (1) ml of distilled water and shake. Add few drops of sodium hydroxide solution and shake again. Slowly add a few drop of 1% Copper (ii) sulphate solution. (iii) Smear the third part on a filter paper, leave for about five (5) minutes and observe carefully
None
Detalles de la respuesta
None
Pregunta 63 Informe
TEST OF PRACTICAL KNOWLEDGE QUESTION
Carefully study specimens J and K and answer questions 4(a) to 4(d).
(a) Name the type of refuse in specimens: (i) J (ii) K.
(b) List three animal vectors of disease causing organisms that breed on a each of specimens J ana K.
(ii) Name four diseases each caused by animal vectors associated with each or specimen J and K.
(c) Name one method of disposal of each of specimens J and K in: (i) rural areas (ii) urban areas.
(d)(i)State four effects of improper disposal of specimen K
(ii) In a tabular form. state five differences between specimens J and K.
(iii) outline one way in which specimen J is of importance to farmers.
None
Detalles de la respuesta
None
Pregunta 64 Informe
TEST OF PRACTICAL KNOWLEDGE QUESTION
Study carefully specimen E and F and use them to answer questions 2(a) to 2(d).
(a) (i) What class of organism do specimen E and F belong to?
(ii) State three similarities between specimen E and F.
(iii) In a tabular form, state three differences between specimens E and F;
(b) State two ways each in which: (i) Specimen E (ii) Specimen F are of economic importance.
(C)(i) State one observable feature each of specimens E and F and how these features adapt the specimens against predation.
(ii) Name the habitats of specimens E and F.
(d) Remove all the wings of specimen E. Make a drawing 8-10 cm long of the dorsal view of specimen E and label fully.
(a)(i) Specimens E and F belong to Class insecta.
(ii) Similarities: Both specimens A and B Possess 6 legs/3 pair of legs; Both specimens A and B have 3 body d thorax and abdomen/segmented body.
Both specimens A and B are bilaterally symmetrical; Both specimens A and B possess mandibles/mandibulate mouth parts;
Both specimens A and B have jointed appendages/ Jointed legs; Both specimens A and B have a pair of antennae.
(iii) Differences:
Specimen E/ Cockroach |
Specimen F/Soldier Termite |
Small head relative to the body, |
Large head related to the body; |
Wings present |
Wings absent; |
Has compound eyes/has sight; |
No eyes /blind/has no sight; |
Dark brown colour, |
light brown colour; |
Small mandibles present |
Large mandibles present; |
(b) Economic Importance:
(i) Specimen E/Cockroach Destroys clothes/ books/ boxes; - contaminates food/ reduces the quality of food; - gives foul odour, serves as a vector of diseases;
(ii) Specimen F/Soldier Termite: Speeds up decaying process/by breaking down of dead trees to form humus which increases soil fertility;
-They destroy wood in roofs/houses /furniture;
-The mud from the termitarium is used in constructing lawn tennis courts/construction of houses;
-For poultry feed/source of protein; Improves soil drainage/aeration through their channels;
- Destroy crops/ timber.
(c)(i) Adaptation of Specimen E/Cockroach Against Predation:- Specimen E has wings to fly away from predators;
-Its brown colour matches with the environment as camouflage against predators; -the flattened shape make it easy to hide in crevices to escape.
Adaptation of Specimen F Against Predation: Presence of mandibles for defense/protection.
-Possesses snout-like projection that produces a poisonous substance for protection.
(ii) Habitat: Specimen E/Cockroach- dark boxes/cupboards, cesspits/any other correct habitat.
(ii) Specimen F/Soldier Termite-Termitarium/termite mold/hill
Detalles de la respuesta
(a)(i) Specimens E and F belong to Class insecta.
(ii) Similarities: Both specimens A and B Possess 6 legs/3 pair of legs; Both specimens A and B have 3 body d thorax and abdomen/segmented body.
Both specimens A and B are bilaterally symmetrical; Both specimens A and B possess mandibles/mandibulate mouth parts;
Both specimens A and B have jointed appendages/ Jointed legs; Both specimens A and B have a pair of antennae.
(iii) Differences:
Specimen E/ Cockroach |
Specimen F/Soldier Termite |
Small head relative to the body, |
Large head related to the body; |
Wings present |
Wings absent; |
Has compound eyes/has sight; |
No eyes /blind/has no sight; |
Dark brown colour, |
light brown colour; |
Small mandibles present |
Large mandibles present; |
(b) Economic Importance:
(i) Specimen E/Cockroach Destroys clothes/ books/ boxes; - contaminates food/ reduces the quality of food; - gives foul odour, serves as a vector of diseases;
(ii) Specimen F/Soldier Termite: Speeds up decaying process/by breaking down of dead trees to form humus which increases soil fertility;
-They destroy wood in roofs/houses /furniture;
-The mud from the termitarium is used in constructing lawn tennis courts/construction of houses;
-For poultry feed/source of protein; Improves soil drainage/aeration through their channels;
- Destroy crops/ timber.
(c)(i) Adaptation of Specimen E/Cockroach Against Predation:- Specimen E has wings to fly away from predators;
-Its brown colour matches with the environment as camouflage against predators; -the flattened shape make it easy to hide in crevices to escape.
Adaptation of Specimen F Against Predation: Presence of mandibles for defense/protection.
-Possesses snout-like projection that produces a poisonous substance for protection.
(ii) Habitat: Specimen E/Cockroach- dark boxes/cupboards, cesspits/any other correct habitat.
(ii) Specimen F/Soldier Termite-Termitarium/termite mold/hill
