Which physiological response is a sign of the body's immediate defense against injury?

Inflammation is a primary physiological response of the body that serves as an immediate defense mechanism against injury or infection. When tissues are damaged or when pathogens invade, the body initiates the inflammatory response, which helps to isolate the affected area, eliminate the harmful agents, and initiate the healing process. This response involves increased blood flow to the affected area, swelling, redness, heat, and pain, due to the release of signaling molecules like histamines and cytokines. These changes attract immune cells to the site of injury, thereby enhancing the body's ability to combat infection and promote repair.

Other options such as metastasis, homeostasis, and osmosis do not specifically relate to the immediate defense against injury. Metastasis refers to the spread of cancer cells from one part of the body to another, which is a pathological process rather than a defensive response. Homeostasis refers to the body's ability to maintain stable internal conditions despite external changes, and while it is vital for overall health, it does not directly indicate a defense mechanism against injury. Osmosis is the movement of water across a semipermeable membrane, which occurs in cellular processes but is unrelated to the body's immediate response to injury.