Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?

Question

Accepted Answer

C. 1. **Recall the muscles involved in normal breathing.** Breathing normally involves both the **diaphragm** (a dome-shaped muscle below the lungs) and the **external intercostal muscles** (which move the ribs).

2. **Understand diaphragmatic breathing.** With **conscious effort**, a person can choose to breathe using **only the diaphragm**, moving it up and down without involving rib movement at all — this is commonly known as **diaphragmatic (belly) breathing**.
$$
	ext{Diaphragm contracts/relaxes} \Rightarrow 	ext{lung volume changes} \Rightarrow 	ext{air moves in/out (ribs stay still)}
$$
This technique is often practiced in yoga and relaxation exercises.

3. **Eliminate the incorrect options.** Exhaled air always contains some oxygen (never zero), air cannot normally be exhaled through the Eustachian tube with nose and mouth closed under typical conditions, and lungs can never be made **fully** empty because residual volume always remains, no matter how forcefully one exhales.

4. **Conclusion.** It is genuinely possible to consciously breathe using only diaphragm movement, without moving the ribs.

Hence, the answer is **C**.