How do platelets function in the body?

Platelets play a crucial role in hemostasis, which is the process that prevents and stops bleeding in the body. When a blood vessel is injured, platelets are activated and quickly move to the site of the injury. There, they adhere to the exposed collagen from the damaged tissue and form a temporary "platelet plug." This plug is vital as it serves as a barrier to blood loss. Additionally, activated platelets release various signaling molecules that further promote clot formation and attract more platelets to the injury site, reinforcing the plug. Eventually, a stable blood clot forms through a series of biochemical reactions involving various clotting factors, leading to the stabilization of the platelet plug. Therefore, the primary function of platelets is to cause blood to clot, making option C the correct choice.

In contrast, while platelets do play a role in the overall maintenance of circulation and can assist in inflammation, they do not transport nutrients, create blood cells, or directly combat infections—functions that are primarily associated with red blood cells, white blood cells, and plasma, respectively. This understanding clarifies why they are not involved in those other processes.