What is the outer part of the eye consists

The outer layer contains the sclera (the white of the eye) and the cornea (the clear dome at the front of the eye). The cornea is like a window into the eye. It lies in front of the iris, the coloured part of the eye

Keeps you from getting lung cancer from smoking

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)