Question

Which of the following groups do not constitute a food chain?

1. Wolf, rabbit, grass, lion
2. Plankton, man, grasshopper fish
3. Hawk, grass, snake, grasshopper, frog
4. Grass, snake, wolf, tiger

Options

• (i) and (iv)

• (i) and (iii)

• (ii) and (iii) 

• (ii) and (iv)

Answer 1

(ii) and (iv)

Explanation:

A food chain must follow a logical sequence where energy flows from producers to primary, secondary, and tertiary consumers. In (ii) Plankton, man, grasshopper, fish, the sequence is incorrect because grasshoppers do not feed on plankton, and humans do not fit naturally in this chain. Similarly, in (iv) Grass, snake, wolf, tiger, the sequence is disrupted as snakes do not consume grass, and both wolves and tigers are apex predators, making it an illogical progression.