Question

One of these is a decomposer a) fungi b)algae c)protozoa d)insect

Answer 1

Decomposers are organisms that break down,  naturally, the organic materials in the environment and aid in the process of the energy cycle. The examples include fungi and bacteria.

Ans- Fungi

Answer 2

Answer: a) Fungi

Explanation:

The decomposer are organisms that feed on the dead organisms. They get energy from the nutrients present in the dead organisms. They are one of the important organisms of the ecosystem because without decomposer, the dead organisms cannot be decomposed.

Common decomposer are fungi and bacteria.

Protozoan and insect are heterotrophs which may acts as decomposers some times.  

But algae comes under plant kingdom which is an autotrophs.  

Thus, fungi is a pure decomposer. Example: mushroom.