Decomposers play a crucial role in the ecosystem as they break down dead organic matter and recycle nutrients back into the environment. They are responsible for the decomposition and recycling of organic materials, ultimately contributing to the nutrient cycle.

The correct answer to this question is option 'C', which states that decomposers include both bacteria and fungi. Let's explore why this is the correct answer in detail.

Importance of Decomposers:
Decomposers are an essential part of the food chain and ecosystem. They break down dead organisms, such as plants and animals, as well as their waste products, into simpler substances. This process releases nutrients back into the soil, water, and air, making them available for other organisms to use. Without decomposers, dead organic matter would accumulate, and the nutrients would remain locked up, leading to a nutrient-poor environment.

Bacteria as Decomposers:
Bacteria are microscopic single-celled organisms that play a vital role in decomposition. They are found almost everywhere, including soil, water, and even inside the bodies of other organisms. Many bacteria are specialized decomposers that can break down complex organic compounds, such as cellulose and lignin, into simpler forms. For example, some bacteria break down dead plant material, releasing carbon, nitrogen, and other nutrients. Others can decompose animal remains or waste materials.

Fungi as Decomposers:
Fungi are another group of decomposers. They are eukaryotic organisms that include molds, mushrooms, and yeasts. Fungi obtain nutrients by absorbing organic matter through their hyphae, which are thread-like structures. They are particularly efficient at breaking down tough substances like lignin, making them important decomposers of wood and plant materials. Fungi also help in recycling nutrients by decomposing dead animals, leaves, and other organic matter.

Other Decomposers:
While bacteria and fungi are the primary decomposers, other organisms also contribute to the decomposition process. For example:

- Some insects, such as beetles and flies, help break down organic matter by feeding on dead plants and animals.
- Earthworms play a crucial role in decomposition by consuming organic matter and excreting nutrient-rich castings.
- Certain species of mites and nematodes also contribute to decomposition by feeding on dead organic material.

In conclusion, decomposers include both bacteria and fungi, along with other organisms like insects, earthworms, mites, and nematodes. They work together to break down dead organic matter, recycle nutrients, and maintain the balance of the ecosystem.