What stage in health Ages 41–64: what health do they keep up of old age

Try tylenol or see a professional

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)

A. vitamin c is your answer