Answer: Peers
Other people for example if they are smoking that can harm you by second hand smoking or persuasion for you to smoke.
Peers can also effect you emotionally by making you cry and angry.
Well mechanical digestion involves physically breaking the food into smaller pieces but chemical digestion involves breaking down into simpler nutrients that can be used by cells.
I think the answer is d. hope this helps you! :)
The answer to your question is,
C. Muscular fitness training strengthens tendons, ligaments, and cartilage.
-Mabel <3