Yooooooooooo answer : yoooooooooooo
I think the answer is proactive
1. eating healthy foods.
2. getting enough sleep.
3. getting enough exercise
4. managing stress
5. washing your hands consistently.
All of those things helps your immune system by strengthening it or by keeping germs away which intern helps prevent you from getting sick.
I hope this helps. Let know if anything is unclear.
B. Lactic acid build up creates pains and aches on the muscles
