(a) (i) List three components of an ecosystem (ii) Describe briefly the interaction among the components named in (a) (i).

(b) List three major steps that are usually taken in studying plants and animals in community.

(c) State the importance of each of the following in a population and explain how each affects the growth of a population:
(i) competition; (ii) pathogens; (iii)water. 
 

(a) (i) List five excretory organs found in living organisms.
(ii) Give one example of an organism in which each type is found.

(b) (i) state two ways in which the excretory organs of earthworm is similar to that of mammals.
(ii) Give three differences between them.

(c) Describe the mechanisms of opening and closing of the stomata. 
 

(a) Describe briefly the process involved in the breakdown of glucose in the cell of living organisms to produce energy (AT P)

(b) State two conditions under which glycogen can be converted to glucose to produce energy.

(c) Describe an experiment to demonstrate that oxygen is released by green plants during photosynthesis. 
 

(a) (i) Give two reasons why termites are described as social insects.
(ii) Name four castes found in the termite nest, stating one of each castes.

(b) Describe five behavioural adaptations of termites which enable them to survive in their environment. 
 

(a) Describe the process of succession in an abandoned farm land.

(b) List seven ways by which micro-organisms can -be controlled to maintain good health.