Decomposers are organisms that

Options

A. Elaborate chemical substances, causing death of tissues
B. operate in living body and simplifying organic substances of cells step by step
C. attack and kill plants as well as animals
D. operate in dead matter, simplifying step by step the organic constituents of dead body

Explanation

### Step-by-Step Solution:

1. **Definition of Decomposers**: Decomposers are organisms that break down dead organic matter. They are essential for the recycling of nutrients in ecosystems.

2. **Nature of Decomposers**: Most decomposers are saprophytic in nature, meaning they obtain their nutrients by feeding on dead and decaying organic material.

3. **Types of Decomposers**: The primary decomposers include saprophytic fungi and bacteria. These organisms play a crucial role in breaking down complex organic substances into simpler compounds.

4. **Role of Decomposers**: Decomposers help in nutrient cycling by converting dead organic matter into simpler substances that can be absorbed by plants. This process enriches the soil and supports plant growth.

5. **Examples of Decomposers**: Earthworms are an example of detrivores, which also assist in the decomposition process by breaking down detritus, such as fallen leaves and dead bodies of plants and animals.

6. **Clarification of Misconceptions**: Decomposers do not harm living organisms; they only act on dead matter. They do not kill plants or living tissues.

7. **Conclusion**: Therefore, the correct understanding of decomposers is that they are organisms that feed on dead organic matter and play a vital role in nutrient cycling.