Which of these represents a correct food chain in nature?

Explanation

This Biology question is asking us to identify the correct food chain in nature from the given options. A food chain is a series of organisms that depend on each other for food. The organisms are arranged in a particular order such that each organism in the chain feeds on the one before it and is, in turn, eaten by the one after it. Option A suggests that crustacea feeds on diatoms, fish feeds on crustacea and man feeds on fish. This is incorrect because man is not usually part of a food chain in nature. Option B suggests the correct food chain in nature: diatoms are eaten by crustacea, crustacea are eaten by fish and fish are eaten by man. This is a correct food chain in nature. Option C suggests that fish feeds on crustacea, crustacea feeds on man and man feeds on diatoms. This is incorrect because it is not usually the case that higher organisms such as man feed on lower organisms in a food chain. Option D suggests that diatoms are eaten by fish, fish are eaten by crustacea and crustacea is eaten by man. This is incorrect because it is not usually the case that higher organisms such as man feed on lower organisms in a food chain. Thus, the correct answer is Option B, which represents a correct food chain in nature.