What does a microscope enable people to do

It allows scientists to see the bio samples with an amount of zoom so they can figure out new discoveries and have an important role in the living evolution

It allows people to see things that you or i cant see with the naked eye

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)