What specific process has been occurring if pus is present around an infected area?

Pus is a thick fluid that consists of dead white blood cells, bacteria, and tissue debris, typically occurring at the site of infection. This presence of pus is primarily associated with inflammation, which is the body's immediate response to infection or injury.

The process of inflammation involves the accumulation of immune cells at the site of an infection, leading to symptoms such as redness, swelling, heat, and pain. Phagocytosis, while an important process in the immune response where phagocytes engulf and digest pathogens, is a component of inflammation rather than an isolated process leading directly to the formation of pus. Vasodilation refers to the widening of blood vessels that occurs during inflammation to increase blood flow to the area, contributing to the redness and heat but not the pus formation itself. Clonal selection relates to the process of activating specific lymphocytes following antigen exposure and is not specifically tied to the presence of pus.

Therefore, the formation of pus is a direct result of inflammation, as it signifies the activity of the immune system in response to infection, illustrating the body's effort to combat pathogens.