Why is it important to specify both magnitude and direction with some measurements and not others?

Other measurements have modulus, but also have a direction and sense, for example: position, speed, these quantities are called vectors.

Explanation:

Some magnitudes have only module for example: time, energy. These quantities are called scalars

Other measurements have modulus, but also have a direction and sense, for example: position, speed, these quantities are called vectors.

For these vector magnitudes, both the magnitude and the direction and the point of application must be given, to have complete information about them

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.