The speed of sound is:

86,000 miles per second
1,100 feet per second
186,000 miles per hour

This isnt health but the answer is 1100 feet per second

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)