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

Stephanie lives in california, and her cousin thomas lives in france. which coordinate system would be most useful if the two wanted to observe the same meteor shower and discuss their observations over online chat as they're making them? a. horizontal b. equatorial c. azimuth-altitude d. celestial or azimuth-altitude