Answer:
torn muscle fibers
Explanation:
due to heavy exercise your muscle fibre start having small micro muscle tears
The immune system fights off the pathogen by Leukocytes also known as white blood cells. When a pathogen enters the body the immune system becomes alert to it and sends out sends out the Phagocytes (a type of Leukocytes) which engulfs the pathogens.
Homeostasis means that body is in balance.