What are decomposers in the detritus food chain primarily composed of?

The correct answer is Option (3) → Fungi and bacteria

There are two kinds of food chain. The grazing food chain starts with green plants. The detritus food chain (DFC) starts with dead organic matter. The DFC is made up of decomposers, which are heterotrophs, mainly fungi and bacteria. They break down the dead matter and absorb the simple substances released.

Option (1) Producers — Incorrect. Producers are green plants and other autotrophs. They make their own food by photosynthesis and form the start of the grazing food chain, not the decomposers.

Option (2) Herbivores — Incorrect. Herbivores are primary consumers that eat living plants. They belong to the grazing food chain.

Option (3) Fungi and bacteria — Correct. Decomposers are mainly fungi and bacteria, which feed on dead organic matter.

Option (4) Carnivores — Incorrect. Carnivores eat other animals; they are secondary or higher consumers in the grazing food chain.

NCERT Extract:
Energy Flow – “… The detritus food chain (DFC) begins with dead organic matter. It is made up of decomposers which are heterotrophic organisms, mainly fungi and bacteria. They meet their energy and nutrient requirements by degrading dead organic matter or detritus. These are also known as saprotrophs (sapro: to decompose).”