Question 11
The Principle of
says to add another kind of exercise to improve
Type
Frequency
Intensity
Time

I don't know for sure but I think it is intensity

Explanation:

The Principle of Intensity

out of the choices i'd say d the ability to set goals, mainly because to desire to continue you need motivation but it isn't motivation in that part, but setting goals means you have an endgame and you want to reach it which sums up motivation.