Name the muscles which facilitate breathing.

Explanation

**Step-by-Step Solution:**

1. **Identify the Primary Muscle for Breathing:**
- The primary muscle that facilitates breathing is the **diaphragm**. It is located beneath the lungs and plays a crucial role in the breathing process.

2. **Understand the Function of the Diaphragm:**
- The diaphragm contracts and relaxes to create changes in the thoracic cavity's volume. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity, which leads to **inspiration** (inhaling air).

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