What is the primary function of platelets in the blood?

The primary function of platelets, also known as thrombocytes, is blood clotting. When a blood vessel is injured, platelets quickly adhere to the exposed tissue and to each other, forming a temporary plug that helps to stop bleeding. This process is critical for maintaining hemostasis, which is the body's ability to prevent and stop bleeding while maintaining normal blood flow.

Platelets contain special proteins and enzymes that are activated during the clotting process, promoting the formation of a stable blood clot. They play a vital role in the coagulation cascade, which ultimately leads to the conversion of fibrinogen to fibrin, solidifying the clot and further preventing blood loss.

In contrast, other functions mentioned in the options are performed by different components of the blood. For instance, red blood cells are responsible for oxygen transport, while plasma proteins transport nutrients and hormones. Therefore, while other options highlight important functions of the blood, they do not pertain to platelets specifically.