Question

wednesday 9/10: respiration lab
why does breathing rate increase after exercise?
a) exercise causes your lungs to get smaller.
b) exercise increases the need for oxygen in muscles, so breathing rate increases to supply more oxygen.
c) exercise makes you tired, so you breathe slower.
d) exercise lowers blood flow, so breathing rate decreases.

Explanation:

To determine why breathing rate increases after exercise, we analyze each option:

• Option A: Exercise does not make lungs smaller. Lungs' size isn't reduced by exercise, so this is incorrect.
• Option B: During exercise, muscles work harder and need more oxygen for cellular respiration (to produce energy). To meet this increased oxygen demand, the breathing rate increases to take in more oxygen and expel more carbon dioxide (a waste product of respiration). This matches the biological process.
• Option C: Exercise makes muscles tired but increases, not decreases, breathing rate as the body needs more oxygen. So this is wrong.
• Option D: Exercise actually increases blood flow (to deliver oxygen and nutrients to muscles) and breathing rate, not lower them. So this is incorrect.

Answer:

B) Exercise increases the need for oxygen in muscles, so breathing rate increases to supply more oxygen