Doctors can directly measure a person's maximum oxygen intake by measuring their oxygen intake while they a. do as many push-ups as possible b. run on a treadmill, which increases speed c. do jumping jacks until they are tired d. sit motionless with a resting heart rate

the person who answered first is right it is the letter B

Explanation:

The appropriate response is B. run on a treadmill, which expands speed. The greatest oxygen admission is estimated during gradual exercise, for example, a sudden spike in demand for a treadmill. It speaks to the physical wellness of an individual and shows their continuance limit during delayed physical action. It is communicated as VO2max (greatest volume of O2) which unit is liter of O2 every moment (L/min)

obviously, the latter.