WAEC Biology 2017 Theory — Question 15

Model answer

(i) Nitrogen fixing bacteria and leguminous plants: The nitrogen fixing bacteria (e.g. Rhizobium) helps the leguminous plant in nitrogen fixation. In return, the plants provide food and shelter for the bacteria. (ii) Algae and fungi in a lichen: The fungi protect the algae and also help in the absorption of water while the food manufactured by the algae benefits the fungi as well. (iii) Sea Anemone and hermit crab: The sea anemone eats the leftover food from the hermit crab. In return, the sea anemone protects the hermit crab from predators.