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

A) it is a percentage of maximum heartrate (roughly 220-agein years)
The target is anywhere from 60%-85%

Bmust be the answer, as technically all organs move, so a is incorrect. all organs are made of different types of cells, so that isn’t a problem, so c is also incorrect. human hearts are very similar to many other animals’ hearts, so d is also incorrect, yet the heart is made of muscle, which is hard to grow in the lab so it would be correct to say b