Which of the following parts of the heart is responsible for preventing the backflow of blood into the left atrium during ventricular systole?

The process by which organisms maintain a stable internal environment is called:

The following are matching items. Match the phrase or term in List A with that in List B by writing its letter in the space provided in the table at the end of the question. LIST A LIST B (i) Storage of genetic material A. Nucleus (ii) Disease caused by deficiency of iodine B. Goitre (iii) Structure for gaseous exchange in insects C. Tracheae (iv) Transports water in plants D. Xylem (v) Hormone that regulates blood sugar E. Insulin (vi) Caused by lack of vitamin B3 F. Pellagra (vii) Blood cells that carry oxygen G. Erythrocytes (viii) Process of cell division in body cells H. Mitosis (ix) Organism that lives on or in another organism I. Parasite (x) Enzyme that digests proteins in the stomach J. Pepsin Answers: LIST A i ii iii iv v vi vii viii ix x LIST B

1. Storage of genetic material (1 mk)
2. Disease caused by deficiency of iodine (1 mk)
3. Structure for gaseous exchange in insects (1 mk)
4. Transports water in plants (1 mk)
5. Hormone that regulates blood sugar (1 mk)
6. Caused by lack of vitamin B3 (1 mk)
7. Blood cells that carry oxygen (1 mk)
8. Process of cell division in body cells (1 mk)
9. Organism that lives on or in another organism (1 mk)
10. Enzyme that digests proteins in the stomach (1 mk)

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(a) Define the term "enzyme". (b) Name three digestive enzymes and their functions. (i) Function: (ii) Function: (iii) Function:

1. Define the term "enzyme". (3 mk)
2. Name three digestive enzymes and their functions. (7 mk)

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What is meant by the term "excretion"?

1. All plants carry out photosynthesis. (1 mk)
2. What is meant by the term "excretion"? (2 mk)
3. The kidneys are responsible for filtering blood. (1 mk)
4. Draw a labelled diagram of the human urinary system. (4 mk)
5. Name two waste products excreted by the kidneys. (2 mk)
6. Viruses can only reproduce inside a host cell. (1 mk)
7. The oesophagus is the site of nutrient absorption. (1 mk)
8. Haemoglobin in red blood cells transports oxygen. (1 mk)
9. All insects have three pairs of legs. (1 mk)
10. The stomata are found only on the upper surface of leaves. (1 mk)
11. Scurvy is caused by a deficiency of vitamin B1. (1 mk)
12. The spinal cord is part of the central nervous system. (1 mk)
13. Fungi reproduce by forming seeds. (1 mk)

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Define the term "food web".

1. Define the term "food web". (2 mk)
2. Construct a food web with at least five organisms, including a producer, primary consumer, and secondary consumer. (4 mk)
3. Explain one significance of food webs in ecosystems. (2 mk)

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What is meant by the term "microorganism"?

1. What is meant by the term "microorganism"? (2 mk)
2. List three beneficial uses of microorganisms. (3 mk)
3. Name one harmful effect of microorganisms. (2 mk)

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Define the term "respiration".

1. Define the term "respiration". (2 mk)
2. Write the word equation for aerobic respiration. (2 mk)
3. List two differences between aerobic and anaerobic respiration. (4 mk)

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Write an essay on cholera using the following guidelines: • Causative agent • Modes of transmission • Symptoms • Effects on the body • Prevention and control measures

1. Write an essay on cholera using the following guidelines: • Causative agent • Modes of transmission • Symptoms • Effects on the body • Prevention and control measures (20 mk)

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Write an essay on the importance of personal hygiene using the following guidelines: • Definition of personal hygiene • Practices of personal hygiene • Importance of personal hygiene • Consequences of poor hygiene

1. Write an essay on the importance of personal hygiene using the following guidelines: • Definition of personal hygiene • Practices of personal hygiene • Importance of personal hygiene • Consequences of poor hygiene (20 mk)

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