Exchange Of Gases

After puberty, larynx grows larger and becomes prominent in man, therefore, called Adam?s apple.

Step 1: Understanding the partial pressure of oxygen.
The partial pressure of oxygen (pO2) in alveolar blood is typically around 40 mmHg, which is the result of the gas exchange between the alveoli and blood in the lungs.
Step 2: Analyzing the options.
(A) 90: Incorrect. This is higher than the typical pO2 in alveolar blood.
(B) 50: Incorrect. This is not the typical pO2 value for alveolar blood.
(C) 104: Incorrect. This value is closer to the pO2 in inspired air, not in alveolar blood.
(D) 40: Correct. This is the typical pO2 in alveolar blood after gas exchange occurs.
Step 3: Conclusion.
The correct answer is (D) 40, as the typical pO2 of alveolar blood is around 40 mmHg.