The answer is true, they are only single celled!
Answer:
The answer is A.
Explanation:
The CR endurance that is given in the question, or cardio respiratory endurance, can be described as the heart's, the muscles' and the lungs' ability to be able to work together effectively through extended periods of physical activity and it can be determined by measuring the amount of oxygen that the body uses in a minute during the said physical activity.
I hope this answer helps.
