B. How much `O_(2)` is carried by (a) 100 ml arterial blood and (b) 100 ml venous blood? (c) Why there is difficulty of respiration at 10,000 ft high altitude?

Explanation

B. (a) `O_(2)` in 100 ml arterial blood = 19-20 ml. (b) `O_(2)` in 100 ml venous blood = 14-15 ml. (c) At 10,000 ft high altitude air is rarefied. As a result of this the partial pressure of `O_(2)(P_(O_(2)))` in the atmosphere becomes low. For this less amount of `O_(2)` enters into the lungs and blood receives less amount of `O_(2)` from the lungs. So respiration becomes difficult.