Body compensates low oxygen availability at high altitudes by

Options

A. increaseing in number of RBC
B. decreasing binding affinity of haemoglobin
C. increasing binding affinity of haemoglobin
D. increasing breathing rate

Answer

To understand how the body compensates for low oxygen availability at high altitudes, we can break down the physiological responses into several steps:

### Step-by-Step Solution:

1. **Understanding High Altitude Effects**: At high altitudes, the atmospheric pressure is lower, which results in a decrease in the partial pressure of oxygen. This means that there is less oxygen available for the body to utilize.

**Hint**: Think about how the environment changes as you ascend to higher altitudes.

2. **Increased Breathing Rate**: To compensate for the lower oxygen levels, the body responds by increasing the breathing rate (hyperventilation). This allows for more oxygen to be taken in with each breath.

**Hint**: Consider how your body reacts when you feel short of breath or are exercising vigorously.

3. **Increased Production of Red Blood Cells (RBCs)**: The body also responds to low oxygen levels by stimulating the production of more red blood cells. This process is regulated by the hormone erythropoietin (EPO), which is produced by the kidneys in response to low oxygen levels. More RBCs mean a greater capacity to transport oxygen throughout the body.

**Hint**: Remember that red blood cells are responsible for carrying oxygen; think about how increasing their number can help in oxygen transport.

4. **Changes in Hemoglobin Affinity**: The affinity of hemoglobin for oxygen can also change. At high altitudes, the body may decrease the binding affinity of hemoglobin for oxygen, allowing for easier release of oxygen to the tissues that need it.

**Hint**: Consider how hemoglobin behaves in different conditions and how it affects oxygen delivery.

5. **Conclusion**: Therefore, the body compensates for low oxygen availability at high altitudes by increasing the breathing rate, increasing the number of red blood cells, and decreasing the binding affinity of hemoglobin for oxygen.

### Final Answer:
The body compensates for low oxygen availability at high altitudes by:
- Increasing the breathing rate
- Increasing the number of red blood cells (RBCs)
- Decreasing the binding affinity of hemoglobin for oxygen