(a) What is a cell?

(b) Describe briefly the structure of DNA.

(c) Describe the process of mitosis

(d) What is the importance of mitosis to living organisms? 
 

(a) What is a sensory cell?

(b) State one function each for the following parts of mammalian eye: (i) lens; (ii) vitreous humour; (iii) optic nerve.

(c) (i) List four structures which protect the eye from injury.
(ii)Explain briefly how each of these structures performs its function.

(d) Explain why a person in a dark room is dazzled for some seconds when he is suddenly exposed to bright sunlight. 
 

(a) List three major zones in the marine habitat stating one characteristic feature of each zone.

(b) (i) Give one example each of plants and animals in the marine habitat.
(ii) Explain how each of the plant and animal is adapted to the habitat.

(c) State three bahavioural adaptations of animals to seasonal changes in terrestrial habitat.

(d) State three characteristics each of the plant community in the tropical rain forest and savanna. 
 

(a) Describe the general arrangement of the viscera of a named mammal.

(b) Describe the process of feeding in (i) Hydra; (ii) Amoeba. 
 

(a) Describe an experiment to demonstrate the effect of auxin on growth of a plant shoot.

(b) List three uses of auxin in agriculture.

(c) Describe the mechanism of transmission of impulses through a nerve fibre.