What component of blood is essential for transporting oxygen?

Red blood cells, also known as erythrocytes, are the component of blood that is essential for transporting oxygen. These cells contain hemoglobin, a protein that binds to oxygen molecules in the lungs and carries them through the bloodstream to tissues and organs throughout the body. The unique structure of red blood cells, which are biconcave in shape, increases their surface area and enables efficient oxygen absorption and release.

In contrast, plasma is the liquid component of blood that carries nutrients, hormones, and waste products but does not play a direct role in oxygen transport. White blood cells are critical for the immune system and help defend the body against infections, while platelets are involved in blood clotting and wound healing. However, none of these components are responsible for the transport of oxygen, making red blood cells the correct answer.