What is the correct mechanism of breathing?

Options

A. Air `to` nostrils `to` lungs `to` nasal cavity
B. Air `to` nostrils `to` nasal cavity `to` lungs
C. Nostrils `to` air `to` nasal cavity `to` lungs
D. Nostrils `to` nasal cavity `to` air `to` lungs

Explanation

### Step-by-Step Solution:

1. **Understanding the Mechanism of Breathing**: Breathing is the process of taking in air (inhalation) and expelling air (exhalation). The mechanism involves several anatomical structures that work together.

2. **Contact with Air**: The first step in the breathing process is to ensure that the body is in contact with air. This is essential for the intake of oxygen.

3. **Entry of Air through Nostrils**: The air enters the body through the nostrils. The nostrils are the external openings of the nasal cavity, which allow air to flow into the respiratory system.

4. **Filtration of Air in the Nasal Cavity**: Once the air enters through the nostrils, it passes into the nasal cavity (referred to as "Nuscle cavity" in the transcript). The nasal cavity has hair-like structures (cilia) and mucus that help filter out dust, pathogens, and other particles from the air.

5. **Air Reaches the Lungs**: After being filtered in the nasal cavity, the air then travels down the trachea and into the lungs, where gas exchange occurs.

6. **Correct Sequence**: Based on the above steps, the correct sequence of the breathing mechanism is:
- Air
- Nostrils
- Nasal Cavity (Nuscle cavity)
- Lungs

7. **Conclusion**: The correct option based on the sequence is option B, which follows the order of air entering through the nostrils, being filtered in the nasal cavity, and finally reaching the lungs.