(a) In a forest the steps of food chain:

Trees (producers) – Deer (primary consumer) – Lion (top consumer).

(b) In a grassland the steps of food chain

Grasses (producers) – rabbit (primary consumer) – snake (secondary consumer) –owl (top consumer).

(c) In a pond the steps of food chain

Algae and aquatic plants (producers) – small fish (primary consumer) – big fish (secondary consumer) –shark (top consumer).