increases
decreases
first increases and then decreases
is not affected
Answer is Wrong!
Answer is Right!
The correct answer is A. When there is a decrease in the concentration of oxygen in the blood, the breathing rate increases. This is because the body needs more oxygen to function properly, and the brain sends a signal to the lungs to breathe faster.
Option B is incorrect because a decrease in oxygen concentration in the blood would cause the body to need more oxygen, not less.
Option C is incorrect because the breathing rate would not first increase and then decrease. It would only increase.
Option D is incorrect because the breathing rate would be affected by a decrease in oxygen concentration in the blood.