What is the function of respiratory part of human
respiratory system?

Options

A. It clears the incoming air from foreign particles
B. It brings the temperature of air upto the body
temperature
C. It transports the atmospheric air
D. It exchanges `O_(2)` and `CO_(2)` between blood and
atmospheric air

Answer

### Step-by-Step Solution:

1. **Understanding the Human Respiratory System**: The human respiratory system is divided into two main parts: the respiratory passage and the respiratory part (or exchange part).

2. **Identifying the Respiratory Part**: The respiratory part is specifically responsible for the exchange of gases. This includes the alveoli, which are tiny air sacs in the lungs where gas exchange occurs.

3. **Function of the Respiratory Part**: The primary function of the respiratory part of the human respiratory system is to facilitate the exchange of oxygen (O2) and carbon dioxide (CO2) between the blood and the atmospheric air.

4. **Distinguishing Between Functions**: It is important to note that other functions such as clearing incoming air from foreign particles, warming the air to body temperature, and transporting atmospheric air are functions of the respiratory passage (which includes structures like the trachea, bronchi, and bronchioles), not the respiratory part.

5. **Conclusion**: Therefore, the function of the respiratory part of the human respiratory system is to exchange O2 and CO2 between blood and the atmospheric air, which occurs in the alveoli.

### Final Answer:
The function of the respiratory part of the human respiratory system is to exchange oxygen (O2) and carbon dioxide (CO2) between the blood and the atmospheric air.

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