Cardiorespiratory fitness is defined as the:

A. the ability of the cardiovascular and respiratory systems to supply oxygen to muscles.
B. the maximal amount of blood expelled per beat.
C. the maximum amount of weight that can be lifted one time.
D. the ability of the muscular system to generate power during interval training.

Option A.

Ability of the cardiovascular and respiratory systems to supply oxygen to muscles.

Explanation:Cardio

Cardiorespiratory fitness is the ability of the cardiovascular and respiratory systems to supply oxygen to the muscles during exercises or physical activities.

It is very important because it bring about wellness to the body.

It reduce the risk of heart diseases, diabetes, strokes and cancer. It also improve lung and heart condition.

Examples of cardiorespiratory fitness are running, jogging, swimming, biking, dancing e.t.c

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.