Which is true about breathing while you exercise? A. You should always hold your breathe when you are working hard. B. If you start breathing fast, you should hold your breath to slow it down. C. If you begin to take deep breaths while you exercise, you should stop because it means you are about to pass out. D. The rate and depth of your breathing changes while you exercise to keep a constant level of blood oxygen and carbon dioxide.

D

Explanation:

A-NOT A U SHOULD NEVER HOLD YOUR BREATHE WHILE EXECISING.

B- NOT B HOLDING YOUR BREATHE DOESNT FIX FAST BREATHING

C- NOT C JUST BECAUSE YOUR BREATHING HEAVY DOES NOT MEAN YOUR ABOUT TO PASS OUT.

D- YES!!! BECUAE THE RATE YOU OUGHT TO BE GOING DETERMINES YOUR LEVEL OF CARBON.

Explanation:

D! hope this helps:) brainliest is appreciated.

a. suckling by young

b. hypothalamus

c. dopamine

d. trh

e. anterior pituitary

f. mammary glands

g. milk production