Select the developmentally appropriate activities a child 6 - 12 months old will master. eating
talking
crawling
standing
walking

Crawling and eating

Crawling & standing should be mastered by one year. For sure. Walking should be between 12 months to 12 1/2 months.

So the answer is standing & crawling.

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)

People who utilizes the progression principle will ensure their exercise program increases in frequency, intensity, time, and type. the changes need to happen gradually in order to ensure they make gains in their fitness program. a person who doesn't utilize the progression principle can still gain health benefits from exercising, but will not continue to improve in cardiovascular fitness.