What is formed by an accumulation of dead white blood cells around regions of infection?

Pus is formed as a result of the accumulation of dead white blood cells, primarily neutrophils, alongside cellular debris and bacteria in response to an infection. When the body encounters an invading pathogen, white blood cells rush to the site of infection to attack and eliminate these invaders. During this process, many white blood cells die, leading to the collection of these cells and fluid, which appears as pus. Pus typically has a thick, yellowish appearance and can be found in abscesses or wounds.

In contrast, phlegm refers to mucus produced in the respiratory system, typically during illnesses like colds or bronchitis, and is not directly related to the accumulation of dead white blood cells. Granulation tissue represents new connective tissue and blood vessels that form on the surfaces of a wound during the healing process, but it does not consist primarily of dead white blood cells. Exudate is a general term for fluid that leaks out of blood vessels into nearby tissues, usually in response to inflammation, but it encompasses various compositions and is not specifically defined as the accumulation of dead white blood cells. Therefore, pus specifically indicates the localized accumulation of dead white blood cells in response to infection, making it the correct answer.