Write a letter on: a friend of yours who has been living in Europe for some years has written to you to join him. write a reply to his letter giving, at least, three reasons why you would rather remain in your country.​

Can you list the drugs that you want answered for? i think maybe your answer could be a or b. but i’ll never know till you post the rest of this question.

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)