Air that remains in lung after most powerful expiration is

Options

A. Inspiratory air
B. Dead space air
C. Tidal air
D. Residual air

Answer

To solve the question "Air that remains in the lung after most powerful expiration is," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We are asked to identify the type of air that remains in the lungs after a forceful exhalation.

2. **Identify Key Terms**:
- **Inspiratory Air**: This refers to the air that is inhaled into the lungs.
- **Tidal Volume**: This is the amount of air that is inhaled or exhaled during normal breathing.
- **Dead Space Air**: This refers to the air that is inhaled but does not participate in gas exchange because it remains in the trachea and bronchi.
- **Residual Air**: This is the air that remains in the lungs after the most forceful expiration.

3. **Analyze Each Option**:
- **Inspiratory Air**: Incorrect, as this refers to air that is taken in, not left in the lungs after exhalation.
- **Tidal Volume**: Incorrect, as this refers to the volume of air exchanged during normal breathing, not what remains after expiration.
- **Dead Space Air**: Incorrect, as this air does not participate in gas exchange and is not what remains after expiration.
- **Residual Air**: Correct, as this is the air that remains in the lungs even after the most powerful expiration.

4. **Conclusion**: The correct answer is **Residual Air**. This is the air that is always left in the lungs after any type of powerful expiration.

### Final Answer:
The air that remains in the lung after the most powerful expiration is **Residual Air**.