Question

Breathing rate increases during physical exercise because

• A. Cells require extra oxygen
• B. Cells require extra energy
• C. Cells require carbon dioxide
• D. Both A and B

Answer 1

The correct option is D Both A and B

Breathing rate is defined as the no. of times a person breathes in a minute. Breathing rate increases during physical exercise because at that time body demands a high amount of oxygen in the blood for metabolism. The body requires extra energy to carry out muscular activity.

So the correct answer is 'Both A and B'.