What two things can you use to determine how hard your body is working? A.) Heart rate and muscle stiffness

B.) Rate of perceived exertion and breathing rate

C.) Muscle stiffness and breathing rate

D.) Heart rate and rate of perceived exertion

It literally could be all of them

Explanation:

Perceived exertion is how hard you feel like your body is working. It is based on the physical sensations a person experiences during physical activity, including increased heart rate, increased respiration or breathing rate, increased sweating, and muscle fatigue.

1. h

2.a

3. i

4. d

5. b

6.f

7.g

8.e

9.c

i hope that this is

answer188 to 210 calories;