What is pus primarily composed of?

Pus is primarily composed of white blood cells, specifically neutrophils, along with debris from dead cells and bacteria. When the body experiences an infection or injury, the immune system responds by sending white blood cells to the affected area to combat pathogens. As these white blood cells work to fight off the infection, they accumulate, die, and contribute to the formation of pus. The presence of dead bacteria and tissue also adds to this mixture, resulting in the thick, often yellowish fluid that is characteristic of pus.

The correct understanding of pus's composition highlights its role in the body's immune response, and why it primarily consists of white blood cells and cellular debris. In contrast, other options relate to different components of blood or tissue but do not accurately represent the biological nature of pus. For instance, red blood cells and plasma are essential components of blood but are not found in pus. Pathogens and toxins may be present in the area of infection but do not form the bulk of pus itself. Skin cells and moisture could be found in wounds but do not constitute pus. Thus, the composition of pus is a critical aspect in understanding how the body reacts to infection and injury.