Final answer:
The three critical concepts of physical assisting are leverage, balance, joint mechanics; awareness; and body alignment in relation to another person. The answer is A. leverage, balance, joint; awareness; alignment.
Step-by-step explanation:
The three critical concepts of physical assisting include leverage and balance, body joint mechanics and awareness, body alignment in relation to the other person. The correct answer is thus A. leverage, balance, joint; awareness; alignment. These concepts are integral to physical therapy and are related to the principles of physics, which help in understanding the mechanical advantage and interactions of forces exerted by and on the human body, such as in the application of Newton's third law and the analysis of free-body diagrams. Physical therapists also need to understand the dynamics of chemical reactions and energy release as they apply to muscle contractions.