Answer the following questions in one or two words or sentences:
Which one out of beetles, roundworm and earthworm are used for vermicomposting and why?

Explanation

**Step-by-Step Solution:**

1. **Identify the Organisms**: The question asks to identify which organism among beetles, roundworms, and earthworms is used for vermicomposting.

2. **Understand Vermicomposting**: Vermicomposting is a process that involves the decomposition of organic waste by earthworms, which helps in enriching the soil.

3. **Determine the Correct Organism**: Among the three options, earthworms are specifically known for their role in vermicomposting. They break down organic matter and improve soil quality.

...