Write one characteristic each of amphibia and aves.

Explanation

### Step-by-Step Text Solution

1. **Identify the Groups**: The question asks for one characteristic each of two groups: Amphibia (amphibians) and Aves (birds).

2. **Characteristic of Amphibia**:
- Amphibians are unique organisms that can live both in water and on land.
- **Specific Characteristic**: They have mucous glands in their skin, which keep their skin moist. This moisture allows them to breathe through their skin in addition to using gills and lungs.

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