List two differences between male and female frog.

Explanation

### Step-by-Step Text Solution

1. **Size Difference**:
- Male frogs are generally smaller in size compared to female frogs. This size difference is a notable characteristic that can be easily observed.

2. **Presence of Vocal Sacs**:
- Male frogs possess vocal sacs, which are balloon-like structures that bulge outward. These sacs play a crucial role in amplifying sound during mating calls. In contrast, female frogs do not have vocal sacs.

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