According to the exercise principle of balance, a workout should
a.
address all components of fitness
b.
focus on balance and coordination
c.
target specific areas for improvement
d.
vary exercise activities over time

answer; i do believe that the correct answer is (b)

age might have something to do with behavior depending on the age because not everyone who is the same age acts the same like 2 year olds could have bad behavior but some won't.

i hope this : )