What is reflex action? What is its significance?

Explanation

### Step-by-Step Solution

1. **Definition of Reflex Action**:
- Reflex action is an involuntary and nearly instantaneous movement in response to a stimulus. It occurs without the involvement of conscious thought, meaning it happens automatically.

2. **Components of Reflex Action**:
- Reflex actions involve a reflex arc, which includes:
- **Receptor**: Detects the stimulus (e.g., pain, heat).
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