Question

In a natural ecosystem, decomposers include.

• A. Microscopic animals
• B. Bacteria and fungi
• C. The above two types of organisms plus microscopic animals
• D. None of the above

Answer 1

The correct option is B

Bacteria and fungi

The correct option is B.

Explanation of the correct options:

1. Bacteria and fungi perform the function of decomposing the dead and decaying organic matter.
2. They digest the dead bodies of living organisms and secrete essential nutrients from them to derive their nutrition.
3. They are known as scavengers as they are responsible for cleaning the environment by feeding the carcasses.
4. Hence, bacteria and fungi lie in the decomposer's trophic level of the ecosystem.

Explanation of the incorrect options:

Option A:

1. Microorganisms compose the organisms which are microscopic and exist in colonies of cells or unicellular. organisms.
2. There are different groups of microorganisms like protozoa, algae, and protists which do not derive their nutrition via decomposition.
3. The protozoa such as paramecium and amoeba have holozoic nutrition (internalization of solid food particles).
4. Some microorganisms like algae perform photosynthesis (synthesis of food via sunlight).
5. Hence, not all microorganisms are decomposers in an ecosystem.

Option C:

1. Different kinds of microscopic animals are dust mites, spider mites, and some crustaceans such as copepods and certain cladoceran, etc.
2. Microscopic animals use different kinds of heterotrophic nutrition.
3. Microscopic animals do not perform the process of decomposition, hence do not fall under the trophic level decomposer of the ecosystem.

Option D:

1. This is an incorrect option.

Final answer: In a natural ecosystem, decomposers include bacteria and fungi.