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. Which of the following scientists was the first to describe a cell?
Explanation:
The correct answer is: C
Robert Hooke was the first scientist to describe and name the "cell" in 1665.
He made this discovery while examining a thin slice of cork under a compound microscope he had improved.
What he observed were small, box-like structures which reminded him of the tiny rooms, or "cells," inhabited by monks in monasteries.
Although he did not see living cells, his work laid the foundation for later scientists to understand the cell as the basic unit of life.
2. Auxins in living organisms are
Explanation:
The correct answer is: C
Auxins are a group of plant hormones that play a vital role in the regulation of plant growth and development.
They are primarily involved in processes such as cell elongation, root initiation, and response to light and gravity.
The most common natural auxin is indole-3-acetic acid (IAA).
Auxins help plants grow toward light (a phenomenon known as phototropism) and are key regulators in plant development and tissue differentiation.
3. Protozoa engulf bacteria by a process known as
Explanation:
The correct answer is: C
Phagocytosis is the process by which certain living cells called phagocytes ingest or engulf other cells or particles.
In protozoa, this is a common method of feeding, especially in species like amoebas.
The cell extends its membrane around the bacteria to form a food vacuole, where the bacteria are digested.
This process helps protozoa obtain nutrients and also serves as a defense mechanism in some other cells, such as white blood cells in animals.
4. Which of the following statements best describes a tissue?
Explanation:
The correct answer is: A
A tissue is defined as a group of similar cells that work together to carry out a specific function.
These cells often have the same structure and are organized in a way that enhances their functional performance.
For example, muscle tissue is made up of muscle cells that contract, while epithelial tissue consists of cells that cover body surfaces.
This level of organization is a step above individual cells and below organs in the biological hierarchy.
The diagram below is an illustration of an organism. Study it and answer questions 5 and 6.
5. The part labelled I is the
Explanation:
The correct answer is: A
Structure I is a tentacle.
Hydra uses its tentacles, which are equipped with stinging cells called nematocysts, to capture and paralyze its prey.
These flexible appendages surround the Hydra's mouth, aiding in feeding.
6. The part that develops into a new organism is
Explanation:
The correct answer is: C
Part III shows a bud.
Hydra reproduces asexually through budding, where a new, genetically identical organism develops as an outgrowth from the parent's body.
This bud eventually detaches and matures into a new Hydra.
7. The function of lysosomes in cells is
Explanation:
The correct answer is: C
Lysosomes are membrane-bound organelles found in animal cells that contain digestive enzymes.
They are responsible for breaking down and recycling various kinds of biomolecules including proteins, lipids, and damaged cellular components.
This process is known as intracellular digestion.
Lysosomes play a crucial role in cellular defense, waste disposal, and maintaining cellular health by removing potentially harmful substances.
The diagram below is an illustration of a biological process. Study it and answer questions 8 and 9.
8. The biological process illustrated is
Explanation:
The correct answer is: B
The biological process shown in the diagram is osmosis.
This is evident from the net movement of water molecules across the semi-permeable membrane.
Water moves from the compartment with a higher concentration of water (lower solute concentration) in diagram A to the compartment with a lower concentration of water (higher solute concentration), resulting in the changes observed in diagram B.
9. Which of the following statements about diagram B is correct? It
Explanation:
The correct answer is: B
Diagram B illustrates the result of osmosis.
It correctly shows the "net movement of the solvent (water)" through the semi-permeable membrane from the left side, where the solute concentration was initially lower, to the right side, where the solute (salt) concentration was higher.
This movement continues until a state of equilibrium or osmotic pressure is reached, influencing the liquid levels in both compartments.
10. The end products of anaerobic respiration in yeast cells are
Explanation:
The correct answer is: A
During anaerobic respiration in yeast cells, glucose is broken down without the use of oxygen.
This process produces carbon dioxide and ethanol as byproducts, along with a small amount of energy.
This is the basis for alcoholic fermentation, which is used in brewing and baking industries.
11. Which of the following plants undergoes epigeal germination?
Explanation:
The correct answer is: D
Epigeal germination is a type of seed germination in which the cotyledons are pushed above the ground.
In orange plants, the hypocotyl elongates and lifts the cotyledons above the soil surface.
This differs from hypogeal germination, seen in maize and rice, where the cotyledons remain underground.
12. Which of the following statements about the protrusions on bones of mammals is correct? They
Explanation:
The correct answer is: C
The protrusions or projections on bones, such as tubercles and processes, serve as points where muscles, tendons, and ligaments attach.
These structures allow muscles to exert force on the bones during movement.
Without these attachment points, effective movement and leverage by muscles would be limited.
13. Which of the following groups of mammals have an open circulatory system?
Explanation:
The correct answer is: A
Arthropods, such as insects, spiders, and crustaceans, possess an open circulatory system.
In this type of system, blood (or hemolymph) is not entirely confined to blood vessels but instead flows freely through body cavities, bathing organs directly.
Mammals, along with birds (Aves), amphibians, and annelids, all have closed circulatory systems where blood flows entirely within vessels.
The diagram below is an illustration of a structure In organisms. Study it and answer questions 14 and 15.
14. The structure is a
Explanation:
The correct answer is: D
The illustrated structure is a gill.
Gills are specialized respiratory organs found in aquatic animals.
They are characterized by their feathery or filamentous structure, which maximizes the surface area available for the efficient exchange of gases between the animal's blood and the surrounding water.
15. The part labelled I is used for
Explanation:
The correct answer is: B
Part I points to the gill filaments.
These filaments are the primary sites for gaseous exchange in aquatic animals.
They possess a large surface area and a rich blood supply, facilitating the diffusion of oxygen from the water into the blood and the diffusion of carbon dioxide from the blood into the water.
16. The kidney will produce less amount of urine when
Explanation:
The correct answer is: C
When the temperature of the environment rises above 38°C, the body tends to lose water through increased sweating.
As a result, the kidneys conserve water by producing less urine to help maintain internal fluid balance.
In contrast, drinking large amounts of water would typically result in increased urine production.
17. Impulses are transmitted across synapses through
Explanation:
The correct answer is: D
Impulses are transmitted across synapses using chemical transmitters, also known as neurotransmitters.
These chemicals are released from the axon terminal of one neuron and bind to receptors on the next neuron, thereby propagating the signal.
This mechanism allows the nervous system to efficiently communicate across cells.
18. A boxer got knocked down during a contest but stood up after 20 seconds. What part of the ear malfunctioned?
Explanation:
The correct answer is: A
The semi-circular canals are responsible for maintaining balance and detecting head movement.
When a boxer is hit and loses balance, it often results from a temporary disruption in the function of the semi-circular canals.
After a few seconds, once equilibrium is restored, the individual can regain balance and stand up.
The diagram below is an illustration of a section of a fruit. Study it and answer questions 19 and 20.
19. The epicarp is drawn in double lines to show that it
Explanation:
The correct answer is: B
The epicarp is shown in double lines to indicate that a scalpel was used to make a transverse cut through the fruit.
This is a standard method in botanical diagrams to reveal internal structures for educational purposes.
20. The arrangement of placenta and ovules in the fruit shows that the
Explanation:
The correct answer is: B
The arrangement of the seeds attached to a central column within the fruit indicates axile placentation.
This type of placentation is characteristic of fruits like citrus.
Furthermore, the image clearly shows a cross-wise cut through the fruit, which is termed a "transverse section", revealing the internal arrangement of the seeds and the structure of the fruit.
21. Which of the following compounds is a primary product of photosynthesis?
Explanation:
The correct answer is: D
Glucose is the primary product of photosynthesis.
During the process, plants use carbon dioxide, water, and sunlight to produce glucose and oxygen.
This glucose serves as an energy source and building block for other organic compounds like starch, cellulose, and even lipids and proteins.
22. What is the function of a bent glass tube inserted into the gas jar for water culture?
Explanation:
The correct answer is: C
In water culture experiments, a bent glass tube is used to blow air into the gas jar.
This supplies oxygen for root respiration and facilitates proper gas exchange.
It ensures that the plant receives sufficient oxygen for cellular processes while submerged in the water solution.
23. Which of the following food tests does not require heating to get results?
Explanation:
The correct answer is: D
The Biuret test is used to detect the presence of proteins in a solution.
It involves adding Biuret reagent to the sample, and a violet or purple color indicates the presence of peptide bonds.
Unlike other tests such as Benedict’s or Fehling’s, the Biuret test does not require heating to show a positive result.
The diagram below is an illustration of the skeletal part of an animal. Study it and answer questions 24 to 26.
24. The part labelled II is characteristic of
Explanation:
The correct answer is: B
The part labeled II highlights the diastema,
a prominent gap in the tooth row located between the incisors at the front and the premolars and molars towards the back of the jaw.
This significant dental feature is most characteristic of herbivorous animals.
In herbivores, the diastema provides essential space that allows the tongue to efficiently manipulate and sort plant material during the process of chewing.
This enables them to thoroughly grind tough plant fibers with their broad molars for effective digestion.
25. The function of the part labelled II is
Explanation:
The correct answer is: B
The function of the diastema, labeled II, is it allows the tongue to roll food. in herbivorous mammals.
More functionally significant for herbivores, the diastema provides a crucial space within the oral cavity that allows the tongue to skillfully manipulate and roll plant material.
This facilitates the movement of food to the grinding surfaces of the premolars and molars, ensuring thorough mechanical breakdown of plant matter before swallowing.
26. The part labelled I is the
Explanation:
The correct answer is: C
The part labeled I points directly to the incisors.
Incisors are the most anterior set of teeth found in the upper and lower jaws of mammals.
They are typically characterized by their sharp, chisel-like shape, which is well-suited for tasks such as cutting, nipping, and gnawing at food.
In herbivorous animals, like the one whose skull is depicted, the incisors play a key role in initially grasping and severing vegetation.
27. Which of the following processes is not for surviving unfavorable conditions?
Explanation:
The correct answer is: D
Swarming refers to a social behavior where animals (especially insects like bees or locusts) move in large groups.
It is not primarily an adaptation to survive unfavorable conditions.
On the other hand, migration, hibernation, and aestivation are direct survival strategies used by animals to avoid extreme environmental conditions like cold, heat, or drought.
28. The following consequences are as a result of bushfires in some countries except that
Explanation:
The correct answer is: D
Bushfires typically destroy vegetation, including young trees, rather than supporting their growth.
The gradual build-up of forest cover is associated with afforestation and natural succession, not bushfires.
Bushfires cause deforestation, loss of soil fertility, destruction of habitats, and contribute to climate change.
29. In a food chain, the highest percentage of energy will be in the
Explanation:
The correct answer is: A
In a food chain, energy decreases as you move from producers to higher trophic levels.
Grass, being a producer, has the highest percentage of energy because it directly harnesses solar energy through photosynthesis.
Only about 10% of energy is transferred to each successive level, meaning consumers like goats and lions receive less energy.
30. Which part of the marine habitat has the least amount of light penetration?
Explanation:
The correct answer is: D
The abyssal zone is the deepest part of the marine environment and receives little to no sunlight.
It is cold, dark, and under high pressure, with specialized organisms adapted to these harsh conditions.
In contrast, the euphotic zone receives the most light and supports photosynthesis, while the littoral and splash zones are closer to the shore and also receive more light.
31. The main function of decomposers in an ecosystem is to
Explanation:
The correct answer is: C
Decomposers, such as bacteria and fungi, break down dead organisms and waste products.
This process releases mineral nutrients back into the soil, making them available for uptake by producers (plants).
Decomposers play a critical role in nutrient cycling and maintaining ecosystem balance.
The diagram below is an illustration of a plant. Study it and answer questions 32 to 33.
32. What is the adaptation of the part labelled X?
Explanation:
The correct answer is: B
The part labeled X is the flower stalk.
Its significant length is an adaptation that allows the flower to reach the surface of the water.
This positioning is primarily to facilitate pollination by making the flower accessible to pollinators such as insects that may land on the water surface or fly just above it.
While reaching sunlight is also important, the extended stalk's main adaptive advantage in this context is for reproductive success through effective pollination.
33. The organism illustrated is a water
Explanation:
The correct answer is: B
The organism illustrated exhibits broad, floating leaves and prominent flowers that emerge to bloom at the water's surface.
These morphological characteristics are typical of a water lily (belonging to the family Nymphaeaceae).
Water lettuce has a different appearance with a rosette of fuzzy leaves. Water ferns and hornworts are distinct groups of aquatic plants with different structures and reproductive strategies.
34. Which of the following instruments is used for collecting small insects from soil litter and crevices?
Explanation:
The correct answer is: C
A pooter is a simple tool used by biologists to collect small insects by suction.
It consists of a jar with two tubes—one for sucking air and the other for drawing in insects.
It is effective in collecting insects from soil litter and crevices without causing harm to the specimens.
35. Houseflies are vectors of the following diseases except
Explanation:
The correct answer is: D
Houseflies are mechanical vectors for diseases like typhoid, cholera, and dysentery because they carry pathogens on their bodies and in their saliva and feces.
Malaria, however, is transmitted biologically by female Anopheles mosquitoes, not houseflies.
Therefore, houseflies are not vectors of malaria.
36. The excretion of uric acid by Agama lizard is an adaptation for
Explanation:
The correct answer is: B
Uric acid is excreted as a paste or solid, which requires minimal water loss.
This is an important adaptation for desert and arid land animals like Agama lizards, helping them conserve water.
It allows survival in dry environments where water is scarce.
37. What is the consequence of killing rare animal species to the ecosystem?
Explanation:
The correct answer is: A
The killing of rare animal species can lead to their extinction, which disrupts ecological balance.
Every species plays a role in the ecosystem, and their loss can lead to cascading effects, affecting other organisms and processes.
Conservation efforts are essential to maintain biodiversity and ecosystem stability.
Use the statements below to answer questions 38 and 39.
I – Turning off the tap when water is not In use
II – Burning bushes to kill mosquito larvae
III – Allowing farmlands to fallow
IV – Making rare animals reproduce in large numbers
38. Which of the following statements are ways of conserving natural resources?
Explanation:
The correct answer is: C
I – Turning off the tap when not in use conserves water.
III – Allowing farmlands to fallow conserves soil nutrients and prevents land degradation.
IV – Making rare animals reproduce in large numbers helps conserve wildlife.
II – Burning bushes harms biodiversity and is not a sustainable method of conservation.
Therefore, statements I, III, and IV are correct.
39. Which of the following resources in the statements is conserved through a biological cycle?
Explanation:
The correct answer is: C
Wildlife conservation through reproduction involves biological cycles such as mating, gestation, and birth.
This is a natural biological process used to increase the population of rare species.
Water and soil conservation are more physical or environmental processes, not primarily biological.
40. An example of discontinuous variation is
Explanation:
The correct answer is: A
Discontinuous variation shows clear-cut, distinct categories with no intermediates. Blood group (A, B, AB, O) is a classic example.
Skin colour and height are examples of continuous variation, which shows a range without distinct categories.
41. The antibodies present in the blood of humans with blood group A is
Explanation:
The correct answer is: C
People with blood group A have A antigens on their red blood cells and produce anti-B antibodies (not anti-A).
Therefore, they cannot receive blood from individuals with B antigens.
42. Which of the people in the following blood groups could donate blood to a patient with blood group A?
Explanation:
The correct answer is: C
Blood group A can receive blood from group A (AA or AO) and group O (OO).
Group B or AB would introduce incompatible antigens.
Therefore, AO, AA, and OO are all compatible donors.
43. The structure of a DNA molecule may be changed through
Explanation:
The correct answer is: D
A mutation is a change in the DNA sequence of an organism.
This change can be caused by environmental factors such as radiation or chemicals, or it can occur naturally during DNA replication.
Mutations can alter the structure of a gene, which may result in changes to a protein and ultimately affect the traits of an organism.
Unlike variation, heredity, or evolution, mutation directly affects the molecular structure of DNA itself.
44. Mendel's second law of inheritance is also known as the law of
Explanation:
The correct answer is: D
Mendel’s second law, called the Law of Independent Assortment, states that different pairs of genes are passed to offspring independently of one another.
This means that the inheritance of one trait (like seed shape) is not affected by the inheritance of another trait (like seed color), provided the genes are on different chromosomes.
This principle helps explain the genetic variation observed in offspring.
45. Observable expression of transmitted traits is referred to as
Explanation:
The correct answer is: C
The phenotype is the physical or observable characteristic of an organism, such as eye color, height, or blood type.
It results from the interaction between an individual's genotype (genetic makeup) and the environment. For example, a plant may have the genotype for tallness, but poor soil may affect its actual height — the phenotype.
A hybrid refers to an organism produced from the crossing of different genetic types, while variation refers to differences between individuals within a species.
Two plants were crossed and the genotypes of the F1 generation were SS, Ss, Ss and ss.
The allele for smooth is S and wrinkled is S.
Use the information to answer questions 46 and 47.
46. The phenotypes of the offspring are
Explanation:
The correct answer is: D
The offspring genotypes are SS, Ss, Ss, and ss.
- SS and Ss both result in the smooth phenotype since the dominant allele S masks the effect of the recessive s.
- ss results in the wrinkled phenotype because there is no dominant allele.
So, there are 3 smooth (SS, Ss, Ss) and 1 wrinkled (ss), giving a phenotype ratio of 3:1.
47. The genotype of the parent plants would be
Explanation:
The correct answer is: C
The F1 genotypes are: SS, Ss, Ss, and ss — this is a classic Mendelian ratio from a monohybrid cross of two heterozygous parents.
When two heterozygous (Ss) individuals are crossed, the possible genotypes of the offspring are:
- SS (1 chance)
- Ss (2 chances)
- ss (1 chance)
So, the parent genotypes must be Ss and Ss to produce the 1:2:1 genotypic ratio.
48. The evidence of evolution is further strengthened by
Explanation:
Correct answer: D
The similarity in embryonic development stages across different vertebrates is strong evidence of a common ancestry.
For example, the embryos of fish, birds, and mammals all show similar features such as gill slits and tails in early stages.
This uniformity suggests that these organisms have evolved from a common ancestor, strengthening evolutionary theory.
49. The evolution of a species is based on the sum total of adaptive changes preserved by
Explanation:
Correct answer: A
Natural selection is the mechanism by which beneficial adaptive traits become more common in a population over generations.
It preserves traits that improve survival and reproduction, gradually leading to the evolution of a new species.
The other options (isolation, speciation, conservation) may contribute, but natural selection is the central process.
50. The Theory that new organs develop when there is the need for them was postulated by
Explanation:
Correct answer: A
Jean Lamarck proposed the theory of use and disuse, which stated that organisms develop new organs or traits when they need them, and unused ones disappear.
For example, he believed the long neck of the giraffe developed because it constantly stretched to reach higher leaves.
While Lamarck's theory was eventually replaced by Darwin's theory of natural selection, it was an important step in evolutionary thought.
