Why are these groups specifically distinguished? What does this question mean?

How would you describe a person at the midpoint of the health continuum? a. extremely ill b. perfectly well c. neither ill nor perfectly well d. unable to move on the continuum

What exercise allows you to specify the muscles to be traineda. i sonicb. anaerobicc. isometricd. aerobic

Arm circles are often effective dynamic stretches for swimmers because they