What is a benefit of quitting tobacco products? After 12 hours, lung function begins to improve. After 10 years, the risk of dying from lung cancer is cut in half. After five years, the risk of having a stroke is cut by 25%. Over time, life expectancy is increased by 15 years.

Primary effectit is the most accurate.

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)

What are the statements? a? b? c? d?