The answer is force because Force is needed to change the direction of a moving mass.
Pay watching the changes in your body
Plasma. Blood is composed of about 55% plasma and 45% formed elements (red blood cells, white blood cells, and platelets)
This is an example of RELEARNING. Relearning is a method of retrieval used to facilitate the remembrance of a memory that has been stored long time ago. Relearning is also called saving method, it can be a mean of measuring retention by measuring how fast one remember forgotten skills that have been learned previously.