Question

how well the heart and lungs deliver oxygen to the muscles during exercise is a key part of which health - related fitness component?
cardio endurance
muscular endurance
flexibility
body composition

Explanation:

To solve this, we analyze each option:

• cardio endurance: It refers to the ability of the heart, lungs, and blood vessels to supply oxygen to working muscles during sustained physical activity. This matches the description in the question.
• muscular endurance: Focuses on a muscle or group of muscles' ability to repeat contractions or hold a position, not on heart - lung oxygen delivery.
• flexibility: Relates to the range of motion in joints, not oxygen delivery by heart and lungs.
• body composition: Deals with the proportion of fat, muscle, bone, etc. in the body, not oxygen delivery during exercise.

Answer:

A. cardio endurance