Complete the following sentence :
A longitudinal wave is composed of compression and ……………………. .

Explanation

To complete the sentence "A longitudinal wave is composed of compression and …………………….," we need to identify the two main components of a longitudinal wave.

### Step-by-Step Solution:

1. **Understanding Longitudinal Waves**:
- A longitudinal wave is a type of wave where the particle displacement is parallel to the direction of wave propagation. This means that as the wave travels, the particles of the medium move back and forth in the same direction as the wave.

2. **Identifying Components**:
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