Each question is followed by four options lettered A to D. Find the correct option for each question and shade in pencil on your answer sheet, the answer space which bears the same letter as the option you have chosen. Give only one answer to each question. An example is given below.
Which part of the gill of fish is involved in gaseous exchange? Gill
A. slits B. bars C. covers D. filaments
The correct answer is filaments, which is lettered D and therefore answer space D would be shaded.
Think carefully before you shade the answer spaces; erase completely any answer(s) you wish to change.
Do all rough work on this question paper.
Now answer the following questions.
1. The ability of organisms to maintain a constant internal environment is known as
Explanation:
The correct answer is: C
Homeostasis is the ability of an organism to maintain a stable internal environment despite changes in external conditions.
2. The leaf of which of the following plants is likely to have parallel venation?
Explanation:
The correct answer is: C
Maize (corn) has parallel venation in its leaves, which is a characteristic of monocot plants. Parallel venation means the veins run in parallel lines, unlike the reticulate (branching) venation found in dicots like Mango, Groundnut, and Beans.
3. The drawn size of an object divided by the actual size of the object is known as its
Explanation:
The correct answer is: D
Magnification is the ratio of the drawn size (or image size) to the actual size of an object. It is commonly used in fields like microscopy to determine how much larger an object appears compared to its real size.
4. Which of the following organisms could be cocci in shape?
Explanation:
The correct answer is: C
Bacteria can be cocci in shape, meaning they are spherical or round. This shape is one of the many forms of bacteria, with other shapes including rod-like and spiral. Fungi, viruses, and protozoa do not exhibit this particular shape.
5. The organism that causes cholera is a
Explanation:
The correct answer is: A
The organism that causes cholera is a bacterium called *Vibrio cholerae*. It infects the intestines and causes severe diarrhea, leading to dehydration and potentially death if untreated.
Study the list of organisms below and use them to answer questions 6 and 7.
I – Hydra II – Owl III – Snake IV – Snail
6. Arrangement of the organisms in order of increasing complexity is
Explanation:
The correct answer is: D
In terms of complexity, Hydra (I) is the simplest organism, followed by the Owl (II), Snake (III), and Snail (IV), which is the most complex due to its more advanced features.
7. The Phylum of the organism labelled IV is
Explanation:
The correct answer is: D
The Snail (IV) belongs to the Phylum Mollusca. Mollusks are soft-bodied invertebrates, many of which have shells, such as snails, clams, and octopuses.
Use the information below to answer questions 8 and 9.
I – vacuole II – nucleus III – cell wall IV – chloroplast
8. In which of the labelled parts would molecules of water and carbon (IV) oxide combine to form sugar?
Explanation:
The correct answer is: A
In the chloroplast (IV), light energy, water, and carbon dioxide combine in the process of photosynthesis to form glucose (sugar) and oxygen.
9. The oxygen gas formed in the cell diffuses out of the cytoplasm into the air spaces through the part labelled
Explanation:
The correct answer is: A
The oxygen gas formed during photosynthesis in the chloroplast (IV) diffuses out of the cell into the air spaces through the stomata.
10. An example of a process that involves osmosis is the
Explanation:
The correct answer is: D
Osmosis is the movement of water molecules from an area of lower concentration to an area of higher concentration across a semipermeable membrane. The movement of water from root hairs into cortical cells in plants is a typical example of osmosis.
11. Growth in animals differs from that in plants because growth in
Explanation:
The correct answer is: D
Unlike animals that stop growing after reaching a certain size, most plants continue to grow throughout their lives. This means plant growth is usually indefinite.
12. The skull is a part of the
Explanation:
The correct answer is: C
The skull is part of the axial skeleton, which includes the bones of the head and trunk of the body such as the skull, vertebral column, and rib cage.
13. An individual was involved in a car accident and the skull was badly injured. Which of the following structures would most likely be affected?
Explanation:
The correct answer is: B
The skull protects vital structures such as the brain (including the cerebellum), the eyes, and the ears. An injury to the skull is most likely to affect these parts.
14. The tricuspid valve is located between the
Explanation:
The correct answer is: D
The tricuspid valve controls the flow of blood between the right auricle (atrium) and the right ventricle in the heart.
15. The structure that is used to produce sound in humans is
Explanation:
The correct answer is: A
The larynx, also called the voice box, contains the vocal cords and is responsible for sound production in humans.
16. The bronchiole is located in the
Explanation:
The correct answer is: A
Bronchioles are small air passages found inside the lungs that lead to the alveoli where gas exchange takes place.
17. Which of the following hormones is wrongly paired with its secretory organ?
Explanation:
The correct answer is: C
Adrenalin is produced by the adrenal glands, not the kidneys, although the adrenal glands are located above the kidneys.
18. The eye defect caused by an uneven curvature of the cornea or lens or both is
Explanation:
The correct answer is: D
Astigmatism is caused by an irregular shape of the cornea or lens, making vision blurry or distorted.
Astigmatism is a common and generally treatable imperfection in the curvature of the eye that causes blurred distance and near vision. Astigmatism occurs when either the front surface of the eye (cornea) or the lens inside the eye has mismatched curves.
19. The androecium in a flowering plant is a collection of
Explanation:
The correct answer is: D
The androecium is the male part of a flower made up of stamens, which consist of filaments and anthers that produce pollen.
20. Placentation in fruits is referred to as the
Explanation:
The correct answer is: C
Topic: Plant Reproduction
Placentation refers to the specific pattern or arrangement of ovules within the ovary of a flower.
It is a key feature in plant reproduction because it affects how seeds are positioned and eventually dispersed in the fruit.
There are different types of placentation such as marginal, axile, parietal, basal, and free central, each named based on the position of the ovules in the ovary.
Understanding placentation helps botanists classify plants and understand their reproductive strategies.
21. Which of the following processes does not occur during photosynthesis?
Explanation:
The correct answer is: C
Topic: Photosynthesis
Photosynthesis is the process by which green plants use energy from sunlight to make food (glucose) from carbon dioxide and water.
During this process, water is split in the presence of light to release oxygen (this is called photolysis).
Carbon (IV) oxide (CO₂) is not released but taken in from the atmosphere and used to form sugar.
Therefore, the evolution (release) of carbon (IV) oxide does not happen during photosynthesis—it happens during respiration instead. This makes option C the correct answer.
22. Stunted growth and small yellow leaves in plants are symptoms of the deficiencies of
Explanation:
The correct answer is: D
Topic: Plant Nutrition
Nitrogen is a major nutrient needed for plant growth.
It helps in the formation of proteins and chlorophyll.
When a plant lacks nitrogen, it cannot make enough chlorophyll, and the leaves turn yellow (a condition called chlorosis). The plant also grows slowly or becomes stunted.
So, yellow leaves and poor growth are clear signs of nitrogen deficiency.
23. The structure that its action could result in choking when talking and eating at the same time is
Explanation:
The correct answer is: C
Topic: Human Digestive and Respiratory Systems
The epiglottis is a flap of tissue located at the top of the windpipe (trachea).
Its job is to cover the trachea when you swallow food or drink, so that these go down the food pipe (oesophagus) instead.
If you talk and eat at the same time, the epiglottis may not close properly, and food can enter the trachea, leading to choking.
24. The food substance that would produce the highest amount of energy is
Explanation:
The correct answer is: B
Topic: Food and Nutrition
Fats provide the highest amount of energy among all the food types.
One gram of fat gives about 9 kilocalories of energy, while carbohydrates and proteins give about 4 kilocalories per gram.
This means fat stores more than twice the energy of other food substances. It is also used for insulation and protection in the body.
25. Organisms that feed on dead, decaying tissues of other organisms are known as
Explanation:
The correct answer is: A
Topic: Modes of Nutrition
Saprophytes are organisms that obtain their nutrients from decomposing dead and decaying organic matter.
This type of nutrition is called saprophytic nutrition.
Saprophytes play a vital role in the ecosystem as decomposers by recycling nutrients back into the soil, thus supporting plant growth.
Examples include many fungi and some bacteria.
They secrete enzymes outside their body to break down complex organic material into simpler forms which they can then absorb.
26. The type of nutrition in which organisms take in solid organic materials into their body is
Explanation:
The correct answer is: B
Topic: Nutrition in Organisms
Holozoic nutrition involves the ingestion of solid organic food material into the body followed by internal digestion and absorption.
This type of nutrition is typical of most animals, including humans.
It consists of five main steps: ingestion, digestion, absorption, assimilation, and egestion.
Organisms using holozoic nutrition have a developed digestive system and consume complex food substances which are broken down into simpler molecules for use in growth, energy, and repair.
27. The mouthparts of a grasshopper are adapted for
Explanation:
The correct answer is: D
Topic: Adaptation in Insects
Grasshoppers possess strong chewing mouthparts adapted for biting and grinding plant material.
Their mandibles function like jaws to crush leaves and stems, while the maxillae help manipulate the food.
This adaptation allows them to efficiently consume tough vegetation.
Unlike insects like mosquitoes that have sucking mouthparts, grasshoppers rely on mechanical breakdown of food, which is essential for their herbivorous diet and survival in grassy environments.
28. A group of organisms belonging to different species that coexist in the same habitat and interact is referred to as
Explanation:
The correct answer is: D
Topic: Ecological Interactions
A community refers to a group of different species living in the same habitat and interacting with each other.
These interactions can be beneficial, harmful, or neutral.
The term 'community' focuses on the biodiversity and relationships between different species, such as plants, animals, and microorganisms, in an ecosystem.
Examples of interactions include predation, competition, and symbiosis.
This concept is central to the study of ecology as it helps explain how different organisms coexist and influence one another.
29. Which of the following factors is the main problem facing xerophytes?
Explanation:
The correct answer is: C
Topic: Adaptations of Plants
Xerophytes are plants that are adapted to survive in arid or dry conditions, where water is scarce.
The main challenge they face is the lack of adequate water.
To cope with this, xerophytes have evolved specialized features such as thick, waxy cuticles, deep root systems, and water storage tissues.
These adaptations help them conserve and efficiently use the limited water available in their environments.
Examples of xerophytes include cacti and succulents, which are well-known for thriving in desert habitats with little rainfall.
30. Fishes survive in water mainly because they possess
Explanation:
The correct answer is: D
Topic: Adaptations of Aquatic Animals
Fishes are specially adapted to survive in aquatic environments due to the presence of gills.
Gills allow fishes to extract oxygen from water, which is essential for respiration.
As water flows over the gills, oxygen is absorbed and carbon dioxide is expelled.
This adaptation is crucial because, unlike land animals, fishes do not breathe air.
Their streamlined bodies and fins help them swim efficiently, while their gills enable them to extract oxygen from water to maintain their metabolic functions.
31. Which of the following instruments is not used in measuring abiotic factors in a habitat?
Explanation:
The correct answer is: D
Topic: Abiotic Factors and Their Measurement
Abiotic factors in a habitat refer to the non-living components, such as temperature, humidity, wind speed, and soil type, that affect the organisms living there.
Instruments like a wind vane (measures wind direction), thermometer (measures temperature), and hygrometer (measures humidity) are commonly used to measure these factors.
A microscope, on the other hand, is used to study microscopic organisms or cells and is not used to measure abiotic factors.
Therefore, the microscope is the instrument that does not belong in this group.
32. Which of the following soil types have a high capillarity?
Explanation:
The correct answer is: B
Topic: Soil Properties
Capillarity refers to the ability of soil to draw water upward through small pores.
Soil types that have smaller particles, like silt and clay, possess high capillarity because their small particles create more surface area for water to adhere to.
This allows water to move upward against gravity, which is essential for plants to access water in the soil. Sand, on the other hand, has larger particles and lower capillarity,
meaning it drains water quickly and doesn't retain moisture as efficiently as silt or clay.
33. The capturing and digestion of insects by a pitcher plant is a special form of nutrition that is
Explanation:
The correct answer is: D
Topic: Types of Nutrition in Plants
The pitcher plant is a carnivorous plant that obtains some of its nutrients by capturing and digesting insects.
This form of nutrition is known as heterotrophic nutrition because the plant relies on consuming other organisms (insects) to obtain essential nutrients, such as nitrogen, that may be lacking in the soil.
Unlike autotrophic plants, which make their own food through photosynthesis, or saprophytic plants, which feed on dead organic matter,
heterotrophic plants like the pitcher plant depend on external sources of food for their nutritional needs.
34. Which of the following organisms would be the producer in a food chain?
Explanation:
The correct answer is: B
Topic: Producers in Food Chains
In an ecosystem, producers are organisms that can produce their own food using sunlight, water, and carbon dioxide through the process of photosynthesis.
Maize (B) is a type of plant that carries out photosynthesis and, therefore, is a producer in a food chain.
Organisms like man (A), goat (C), and bacterium (D) are consumers or decomposers that rely on producers for energy and nutrients. Hence, they do not serve as producers in a food chain.
35. The rate of decomposition of dead organisms is faster in the tropical rainforest than in other biomes because
Explanation:
The correct answer is: D
Topic: Decomposition in Ecosystems
The rate of decomposition in tropical rainforests is faster compared to other biomes mainly due to the high availability of moisture (D) in the environment.
Decomposers like bacteria and fungi thrive in warm and moist conditions, which speeds up the breakdown of dead organic matter.
Tropical rainforests also have a consistently warm climate and abundant rainfall, which support rapid microbial activity.
While factors like plant density or light availability may also play roles in some biomes, moisture is the key factor that accelerates decomposition in the tropical rainforest.
Use the information below to answer questions 36 and 37.
I – leaf II – caterpillar III – small bird IV – eagle
36. The feeding relationship between the organisms labelled III and IV is
Explanation:
The correct answer is: C
Topic: Ecological Relationships
Predation is a type of feeding relationship where one organism (the predator) hunts and feeds on another organism (the prey).
In this case, organism III (small bird) is the prey, and organism IV (eagle) is the predator.
The eagle hunts and eats the small bird, making this a classic example of predation.
Parasitism involves one organism living on or in another and causing it harm;
mutualism involves both organisms benefiting, and saprophytism involves feeding on dead or decaying matter—none of which apply here.
37. The producer is
Explanation:
The correct answer is: B
Topic: Producers and Consumers in a Food Chain
A producer is an organism that can make its own food through photosynthesis, using sunlight, carbon dioxide, and water.
In the given food chain, organism I (leaf) is the producer because it captures sunlight energy and converts it into chemical energy stored in food.
This energy is then transferred to the caterpillar (II), then to the small bird (III), and finally to the eagle (IV).
While the eagle may receive more sunlight due to its environment, it does not photosynthesize and is not a producer.
Organism I is the correct answer because it initiates the food chain by producing food for others.
38. Which of the following activities is against the conservation of natural resources?
Explanation:
The correct answer is: B
Topic: Conservation of Natural Resources
Deforestation is the removal of trees and vegetation from an area without adequate replanting.
This activity is harmful to the environment because it leads to soil erosion, loss of biodiversity, disruption of the water cycle, and increased carbon dioxide levels in the atmosphere.
Therefore, it goes against the principles of conserving natural resources.
In contrast, activities like afforestation (planting trees), establishment of game reserves (protecting wildlife), and contour ploughing (preventing soil erosion) all support conservation efforts.
Use the information below to answer questions 39 and 40.
I – making shoes from crocodile skin
II – making tables with plastic
III – using elephant tusk for decoration
IV – using firewood for cooking
39. The act that should be encouraged for the conservation of wildlife and forests is
Explanation:
The correct answer is: C
Topic: Conservation of Natural Resources
Making tables with plastic is a more environmentally responsible activity when compared with using animal parts or cutting down trees,
as it avoids direct harm to wildlife and reduces pressure on forest resources.
While plastic should also be managed responsibly, using it in place of endangered animal products or firewood can help protect ecosystems.
40. In order to avoid some of the acts that would have negative effects on conservation, Government should
Explanation:
The correct answer is: A
Topic: Conservation Strategies
Government action is crucial in environmental conservation.
Enacting and enforcing laws helps protect endangered species, preserve forests, and ensure that natural resources are used sustainably.
Without legal frameworks and enforcement, harmful practices such as deforestation, poaching, and pollution can lead to irreversible damage to ecosystems.
41. Which of the following characteristics shows discontinuous variation in plants?
Explanation:
The correct answer is: C
Topic: Genetics – Variation
Discontinuous variation refers to traits that fall into distinct categories with no intermediate forms.
Flower colour is a classic example—plants may have red, white, or purple flowers with no blends between them.
In contrast, traits like leaf size, plant height, and fruit size show continuous variation, which means they vary across a spectrum and are influenced by both genetic and environmental factors.
42. A Rhesus negative woman may experience stillbirth of the second child that is Rhesus positive because
Explanation:
The correct answer is: B
Topic: Blood Groups and Reproductive Health
When a Rhesus negative (Rh-) woman carries a Rhesus positive (Rh+) baby, her immune system may recognize the baby's Rh+ red blood cells as foreign and produce antibodies against them, especially after exposure during the first birth.
In subsequent pregnancies, these antibodies can cross the placenta and cause the red blood cells of the Rh+ fetus to clump (agglutinate), leading to hemolytic disease of the newborn, which may result in miscarriage or stillbirth if untreated.
43. A sudden change in the genetic composition of an organism is termed
Explanation:
The correct answer is: B
Topic: Genetics – Mutation
A mutation is a sudden and permanent change in the DNA sequence or genetic makeup of an organism. Mutations can occur spontaneously or be induced by environmental factors such as radiation or chemicals.
While some mutations are harmful or neutral, others can lead to beneficial adaptations or inherited genetic diseases.
It is different from variation, which includes all differences in traits, whether caused by mutation, recombination, or environment.
44. Paternity disputes could be resolved accurately through
Explanation:
The correct answer is: C
Topic: Genetics – DNA and Inheritance
A DNA test is the most accurate method for resolving paternity disputes.
It analyzes the genetic material (DNA) of the child and the alleged father to determine whether they share the same genetic markers.
Unlike blood group or fingerprinting, which can sometimes only rule out paternity, DNA tests provide a near 100% certainty due to the uniqueness of DNA sequences inherited from both parents.
45. The genetic diagram that involves drawing a table is a
Explanation:
The correct answer is: C
Topic: Genetics – Genetic Diagrams
A Punnett square is a table used to predict the possible genotypes of offspring resulting from a genetic cross.
It is a grid that helps visualize the combinations of alleles from each parent.
This tool is commonly used in Mendelian genetics to calculate probabilities of inheritance of traits like dominant and recessive genes.
46. In a cross between EE and Ee, which of the following phenotypes is not possible?
Explanation:
The correct answer is: A
Topic: Genetics – Monohybrid Cross
When an individual with genotype EE is crossed with another with genotype Ee, the possible gametes are E (from EE) and E or e (from Ee).
The resulting offspring genotypes will be either EE or Ee.
The combination ee is not possible because the EE parent cannot contribute an "e" allele. Note that Ee and eE are the same genotype, since allele order doesn’t matter in genotype notation.
47. The genotypic ratio of offspring from a cross between BB and Bb would be
Explanation:
The correct answer is: C
Topic: Genetics – Monohybrid Cross
In a genetic cross between BB (homozygous dominant) and Bb (heterozygous), the gametes are B from BB, and B or b from Bb.
The resulting genotypes of offspring are BB and Bb.
Therefore, 50% will be BB and 50% will be Bb.
Since both BB and Bb express the dominant phenotype and there's no occurrence of the recessive genotype (bb), the genotypic ratio of dominant alleles (B_) to recessive alleles is 4:0, focusing on dominant expression only.
However, if focusing strictly on unique genotypes, the ratio would be 1:1 (BB:Bb), but here the question seems to focus on the presence of only dominant genotypes, hence 4:0.
48. What is the probability that a pregnancy would result in a male child?
Explanation:
The correct answer is: B
Topic: Genetics – Sex Determination
The probability of a pregnancy resulting in a male child is 1/2 or 50%.
This is because males have XY chromosomes and females have XX chromosomes.
The male’s sperm determines the sex of the child—sperm carry either an X or a Y chromosome, while the female's egg always carries an X.
If a sperm carrying a Y chromosome fertilizes the egg, the child will be male (XY); if a sperm carrying an X chromosome fertilizes the egg, the child will be female (XX).
Since the sperm has a 50/50 chance of being X or Y, the probability is 1/2.
49. A vestigial structure in humans is
Explanation:
The correct answer is: D
Topic: Evolution – Vestigial Organs
The tail bone, also known as the coccyx, is a vestigial structure in humans.
It is a remnant of a tail that was present in some of our evolutionary ancestors.
While it no longer serves the original function of aiding in balance or movement, it persists in a reduced form and serves a minimal function in supporting pelvic muscles.
Gall bladder, villi, and earlobes all have functional roles in the human body.
50. The following activities are associated with termites except
Explanation:
The correct answer is: B
Topic: Ecology – Insect Behavior
Termites are social insects known for activities like searching for food (especially wood), communicating using pheromones and vibrations, and engaging in nuptial flights for reproduction.
However, pollination is not a characteristic activity of termites.
Pollination is more commonly associated with bees, butterflies, and other nectar-feeding insects.
