Your body can get antibodies from A. immunizations.
B. being exposed to the virus or antibody and having your immune system make it.
C. none of the above.
D. all of the above.

I believe it is all of the above.

True! is the answer hope this

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)