Olympic athletes have lower resting heart rates because...
A. their lungs tend to be naturally larger.
B. they exercise regularly, which improves the efficiency of their heart.
C. they tend to eat low-fat diets.
D. they have a lot of muscle mass due to weightlifting.
Both B and C are technically correct, but in the case of athletes...since exercise is proven to strengthen the heart and in turn decrease the heart rate... B is the best answer. Have a nice day!
