I think its d. the client has to be able to be comfortable with the exercise. idk if that's correct, but itd be my opinion.
This answer is true because the group is so then the teacher can focus on them and no making other dessicions. But some teachitheer do the oppisite.
The answer is the placement of the load and the placement of the force applied.
His reflexes. He reacted to the sound quickly, but his motor cortex didn't fire quickly enough to cause his muscles to move in time.
