What are viroids and prions ? Where are they found and what role they play ?

Explanation

### Step-by-Step Solution:

1. **Definition of Viroids**:
- Viroids are small, circular pieces of single-stranded RNA that lack a protein coat. They are the smallest known infectious agents and consist solely of nucleic acid.

**Hint**: Remember that viroids are made only of RNA and do not have any protein components.

2. **Location of Viroids**:
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