Which of the following statements is correct ?

Options

A. inspiration is an active process
B. inspiration is a passive process
C. expiration is an active process
D. both expiration and inspiration are passive processes

Answer

To determine which statement is correct regarding the processes of inspiration and expiration, let's analyze each statement step by step:

### Step 1: Understanding Inspiration
- **Definition**: Inspiration is the process of taking in fresh atmospheric air into the lungs.
- **Nature of the Process**: It is an active process because it involves the contraction of the inspiratory muscles (like the diaphragm and intercostal muscles) which require energy to perform this action.

### Step 2: Understanding Expiration
- **Definition**: Expiration is the process of expelling air out of the lungs.
- **Nature of the Process**: It is generally considered a passive process. During expiration, the inspiratory muscles relax, and the elastic recoil of the lungs helps push the air out without requiring additional energy.

### Step 3: Analyzing the Statements
1. **Statement A**: "Inspiration is an active process."
- This is correct based on our understanding that it requires muscle contraction and energy.

2. **Statement B**: "Inspiration is a passive process."
- This is incorrect because inspiration requires active muscle engagement.

3. **Statement C**: "Expiration is an active process."
- This is incorrect as expiration is primarily a passive process due to muscle relaxation.

4. **Statement D**: "Both expiration and inspiration are passive processes."
- This is also incorrect because inspiration is an active process.

### Conclusion
Based on the analysis, the correct statement is:
- **Option A**: "Inspiration is an active process."