Questions: Challenge Exam Biology 44 of 100 What happens to the air that you breathe in as it passes along the respiratory tract? It is cooled. It is dried. It is warmed and moistened. It is contaminated.

The answer is the third one: it is warmed and moistened.

Explanation for each option:

1. It is cooled: This is incorrect. The air is not cooled as it passes through the respiratory tract. Instead, it is typically warmed to match the body's internal temperature.

2. It is dried: This is incorrect. The air is not dried; rather, it is moistened. The respiratory tract adds moisture to the air to prevent the drying out of the delicate tissues in the lungs.

3. It is warmed and moistened: This is correct. As air passes through the nasal passages and the rest of the respiratory tract, it is warmed to body temperature and moistened by the mucous membranes. This process helps to protect the respiratory system and improve the efficiency of gas exchange in the lungs.

4. It is contaminated: This is incorrect. While the air we breathe can contain contaminants, the respiratory tract has mechanisms, such as mucus and cilia, to filter and trap particles, reducing contamination before the air reaches the lungs.

In summary, as air passes along the respiratory tract, it is warmed and moistened to prepare it for efficient gas exchange in the lungs.