What health benefits do probiotics provide?

a. they build strong bones
b. they are good for the eyes
c. they aid the growth of muscles
d. they keep the stomach healthy

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.

What are the items? ?