Which is true about target heart rate?
a. it varies by a person's body weight.
b. people in poor physical condition should exercise above their target heart rate until they are in better shape.
c. it is a percentage of your maximum heart rate.
d. it is a measure of the heart rate after 20 minutes of exercise.?

I believe that the answer is C. It is a percentage of your maximum heart rate

Well if you pick a machine to work on and that's gonna be your exercise if you don't stick to that machine your muscle strength your muscle mass rather will change because you haven't been doing it you change something in your exercise routine which changes your body's form of dealing with things for example you might become weaker or stronger depending on what kind of exercises you do in whether or not the machine you picked actually your muscles grow.

Cis the most source of vitamins