What process involves the body's response to injury that includes heat, redness, swelling, and pain?

The process described involves the body's inflammatory response, which is characterized by the classic signs of heat, redness, swelling, and pain. Inflammation occurs when tissues are injured or infected and is a critical part of the body's immune response. It serves to isolate and eliminate the source of injury, promotes healing, and helps prevent further damage.

When tissue is damaged, the body releases chemicals that increase blood flow to the affected area, which accounts for the heat and redness. Increased permeability of blood vessels allows fluid and immune cells to enter the tissue, resulting in swelling. The accumulation of fluid and the action of immune cells can stimulate pain receptors, leading to the sensation of pain.

Overall, inflammation is an essential process that protects the body and initiates the healing process, making it the correct choice in response to the question. Other processes like phagocytosis, fever, and immunity are related but do not specifically encompass the set of signs mentioned.