How do humans acclimatise at high altitudes where atmospheric pressure is low for normal breathing?

By increasing red blood cell production, decreasing the binding affinity of haemoglobin and by increasing breathing rate

 The correct answer is Option (2) -By increasing red blood cell production, decreasing the binding affinity of haemoglobin and by increasing breathing rate

The correct option is: By increasing red blood cell production, decreasing the binding affinity of hemoglobin, and by increasing breathing rate.

When humans acclimatize to high altitudes where atmospheric pressure is lower, several physiological adaptations occur to ensure sufficient oxygen delivery to tissues. These adaptations help the body cope with the lower partial pressure of oxygen in the air. Here's an explanation of the processes involved:

1. Increasing Red Blood Cell (RBC) Production: At higher altitudes, where oxygen availability is reduced, the body responds by producing more red blood cells. This is known as polycythemia, and it helps enhance the oxygen-carrying capacity of the blood.
2. Decreasing the Binding Affinity of Hemoglobin: Hemoglobin is the protein in red blood cells that binds with oxygen. To facilitate the release of oxygen to tissues, the binding affinity of hemoglobin decreases at higher altitudes. This means that oxygen is more readily released from hemoglobin, aiding its delivery to tissues.
3. Increasing Breathing Rate: At high altitudes, where there is lower atmospheric pressure, the partial pressure of oxygen in the air decreases. To compensate for this, individuals acclimatize by increasing their breathing rate. This helps bring more air into the lungs, facilitating a higher oxygen uptake.

These adaptations collectively contribute to improving oxygen delivery to tissues, helping individuals acclimate to the challenges of reduced atmospheric pressure at high altitudes.