The diagram given below shows a river and the types of land uses on two sides of the river in a countryside.
The water quality of the river was studied by measuring the amount of dissolved oxygen and ammonia in the water, collected at sites X, Y and Z. The results are presented in the table below:
(i) Explain why site Fhas the lowest content of dissolved oxygen.
(ii) Why are very few fishes found at site ‘Z’?
(iii) Which organism will thrive just after site ZP