Which of the following constitute a food chain?
(a) Grass, wheat and mango
(b) Grass, goat and human
(c) Goat, cow and elephant
(d) Grass, fish and goat

Correct Answer: (b) Grass, Goat, and Human

Explanation:

The grass is a producer, a goat is a primary consumer (herbivore), and a human is a secondary consumer (omnivore).

A food chain comprises a producer, primary consumer, secondary consumer, and decomposer, where one organism in the chain is the energy and nutrient source for another organism.

• Grass, wheat, and mango are producers.
• Goats, cows, and elephants are the primary consumers.  
• Grass is the producer, while fish and goats are the primary consumers, so they cannot constitute a food chain.