The number of RBCs increases if one lives at a higher altitude because

Options

A. (a) there is less oxygen in mountains
B. (b) there is more oxygen at the mountains
C. (c) there are no germs in the air in mountain
D. (d) more heat is required to be produced in the body for keeping warm

Answer

**Step-by-Step Solution:**

1. **Understanding the Environment at High Altitudes:**
- At higher altitudes, the atmospheric pressure decreases, which leads to a decrease in the partial pressure of oxygen. This means that there is less oxygen available in the air compared to lower altitudes.

2. **Recognizing the Effects of Low Oxygen:**
- The decrease in oxygen availability can cause altitude sickness, also known as acute mountain sickness (AMS). Symptoms include headache, nausea, vomiting, and shortness of breath, which can occur shortly after reaching high altitudes.

3. **Physiological Adaptation:**
- To cope with the low oxygen levels, the body undergoes physiological adaptations. One of the primary adaptations is the increase in the production of red blood cells (RBCs).

4. **Role of Red Blood Cells:**
- Red blood cells are responsible for transporting oxygen throughout the body. By increasing the number of RBCs, the body enhances its ability to carry the limited oxygen available at high altitudes to various tissues and organs.

5. **Conclusion:**
- Therefore, the number of RBCs increases in individuals living at higher altitudes as a response to the lower oxygen levels, allowing for better oxygen transport and reducing the effects of altitude sickness.

**Final Answer:**
The number of RBCs increases if one lives at a higher altitude because there is less oxygen available in the atmosphere at high altitudes, prompting the body to produce more RBCs to efficiently transport the available oxygen.

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