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BIOLOGY
FORM 4
PAPER 1
END-TERM 1 2025 EXAM
NAME................................................CLASS................................ADM.......................
Answer all the questions in the spaces provided.
1. State two characteristics of organisms that are easily observed in both animals and plants. (2 marks)
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2. Fingerlings of fish were introduced to two different ponds. Those fingerlings in bond one all died
within four days but the fingerlings in pond two survived.
Suggest the likely reasons why the fingerlings in pond one died. (3 marks)
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3. A student observing a specimen through a microscope viewed a blurred image of the specimen.
Suggest two possible reasons for this observation. (2 marks)
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4. In what ways does Lamarck’s theory fail to agree with modern scientific evidence (2 marks)
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5. Distinguish between convergent and divergent evolution. (1 mark)
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6. (a) Terrestrial insects such as locusts were captured and their blood was analysed. It was found that
the blood does not have blood pigments such as haemoglobin. Explain. (2 marks)
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(b) State how the tracheal system in insects is adapted to gaseous exchange. (3 marks)
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7. State two functions of a diastema in herbivores. (2 marks)
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8. A girl could clearly read the book placed 10cm away but could not identify her friend 10 metres
away.
a) What eye defect was she suffering from? (1mk)
b) Explain why she could not identify her friend but could read the book. 2mks
c) Explain how the defect can be corrected. 1mk
9. Explain two ways in which the chloroplast is adapted to photosynthesis. (2 marks)
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10. The diagram shown below represent cells from a certain type of epithelial tissues in mammals.
(a) Name the part labeled V. (1 marks)
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(b) Identify the region of the mammalian body where the epithelial tissue maybe found. (1 mark)
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(c) What is the role of the numerous mitochondria in the epithelial cells as shown above. (2 marks)
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11. Explain what would happen to red blood cells if blood glucose concentration increased due failure of
the secretion of insulin. (3 marks)
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12. State three biotic factors that could affect an antelope living in Masai Mara. (3 marks)
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13. A drop of a person’s blood shows clumping in serum of blood group B but not in serum of blood
group A.
(a) Identify the blood group of this person. (1 mark)
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(b) Name the antibodies found in blood of the following groups. (2 marks)
(i) Blood group A
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(ii) Blood group AB
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14. list three methods used to show energy flow through the ecosystem. (3 marks)
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15. Name three organelles that would be abundantly present in secretory cells. (3 marks)
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16. Give three ways in which the red blood cell is adapted to transport oxygen? (3 marks)
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17. Describe how the leaves of submerged plants are adapted to gaseous exchange. (2 marks)
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18. Name the part of the seed whose growth brings about epigeal germination. (1 mark)
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19. State three aspects of light that affect the rate of photosynthesis. (3 marks)
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20. (a) Identify the class with organisms that have three body parts and three pairs of legs. (1 mark)
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(b) Suggest three reasons why members of the class named in (a) above are adapted to all types of
habitats. (3 marks)
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21. (a) List three types of gene mutation. (3 marks)
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(b) (i) What are sex-linked genes? (1 mark)
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(ii) Name two conditions that are sex-linked. (2 marks)
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22. (a) State any two rules of binomial nomenclature. (2 marks)
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(b) Define the term species. (2 marks)
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23. (a) Name two digestive enzymes produced in their inactive form. (2 marks)
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(b) Explain why the enzymes named in (a) above are produced in inactive form. (2 marks)
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24. (a) Define immunity. (1 mark)
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(b) Giving an example in each case, give two main types of immunity. (4 marks)
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25. State three advantages of cross-pollination. (3 marks)
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26. State three factors that increase the rate of traspiration. (3 marks)
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