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

Options

A. one can breathe out air totally without oxygen
B. one can breathe out air through eustachian tubes by closing both the nose and the mouth
C. one can consciulsly breathe in and breathe out by moving the diaphragm alone without moving the disphragem alone without moving the rigbs at all
D. the lungs can be made fully emplty by forcelfuly breathing out all air form them

Answer

To solve the question regarding the possibilities of conscious breathing, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Breathing**: Breathing involves inhaling oxygen and exhaling carbon dioxide. This process is known as respiration. The air we breathe in contains about 20.84% oxygen, while the air we breathe out contains about 15.7% oxygen.

2. **Analyzing the Options**:
- **Option A**: "One can breathe out air totally without oxygen."
This is incorrect because even when we exhale forcefully, some residual air (which contains oxygen) remains in the lungs.

- **Option B**: "One can breathe out air through ostachian tubes by closing the mouth and the nose."
This is also incorrect. The Eustachian tubes (often misspelled as ostachian) connect the middle ear to the nasopharynx and are not designed for breathing out air. They help equalize pressure in the ear, not facilitate breathing.

- **Option C**: "One can consciously breathe in and out by moving the diaphragm alone without moving the ribs at all."
This is a possibility. While it is more common to use both the diaphragm and the rib muscles for breathing, it is possible to consciously control the diaphragm to breathe without moving the ribs.

- **Option D**: "The lungs can be made fully empty by forcefully breathing out to form them."
This is incorrect because there is always some residual volume of air left in the lungs after maximum exhalation, which is typically around 500 ml.

3. **Conclusion**: After analyzing all the options, the correct answer is **Option C**: "One can consciously breathe in and out by moving the diaphragm alone without moving the ribs at all."