The total number of alveoli present in both the lungs of man is

Options

A. 30 lakh
B. 30 million
C. 400 million
D. 300 million

Answer

To determine the total number of alveoli present in both the lungs of a human, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Alveoli**:
- Alveoli are tiny, sac-like structures in the lungs where the exchange of oxygen and carbon dioxide occurs. They are the final branching of the respiratory tree and are highly vascularized, meaning they have a rich supply of blood vessels.

**Hint**: Remember that alveoli are crucial for gas exchange in the lungs.

2. **Consider the Total Lung Volume**:
- The number of alveoli is related to the total lung volume. Generally, larger lungs will contain more alveoli.

**Hint**: Think about how lung size might affect the number of alveoli.

3. **Estimate the Number of Alveoli**:
- Research and scientific studies indicate that the average number of alveoli in a human's lungs is approximately 300 million.

**Hint**: Look for reliable sources or textbooks that provide data on human anatomy for verification.

4. **Select the Correct Option**:
- Given the options: 30 lakh, 30 million, 400 million, or 300 million, the correct answer is 300 million.

**Hint**: Compare the numbers given in the options with your estimate to find the correct one.

### Final Answer:
The total number of alveoli present in both the lungs of a man is approximately **300 million**.