Breathing and exchange of gases practice · Medium

Option B (Upper - Diaphragm) is the incorrect match because the diaphragm forms the lower boundary, not the upper boundary, of the thoracic chamber.

Option D (Vital capacity) is correct because vital capacity is defined as the total volume of air a person can expire after a forcible inspiration.

Option A (40 mm Hg) is correct because the partial pressure of oxygen in the blood flowing through the pulmonary artery is deoxygenated blood returning from the body.

Option D (Only II) is correct because frogs use their skin as an accessory respiratory organ, especially when in water.

Option B ($PO_2 \downarrow , RBC \uparrow , \text{Breathing rate} \uparrow$) is correct because at higher altitudes, the partial pressure of oxygen decreases, stimulating increased RBC production and a higher breathing rate to compensate for the lower oxygen availability.

Option A (If both Assertion and Reason are true and Reason is the correct explanation of Assertion) is correct because aerobic animals can produce lactic acid anaerobically under certain conditions, making them not truly aerobic.