Which component of blood binds oxygen molecules?

The correct answer is C, erythrocytes, also known as red blood cells. Erythrocytes are specialized cells in the blood that play a crucial role in transporting oxygen from the lungs to the rest of the body. They contain a protein called hemoglobin, which has a high affinity for oxygen. When blood passes through the lungs, hemoglobin binds with oxygen molecules, forming oxyhemoglobin. This process allows erythrocytes to carry large amounts of oxygen efficiently throughout the circulatory system.

In addition to oxygen transport, erythrocytes also help in transporting carbon dioxide, a waste product of metabolism, back to the lungs for exhalation. The unique biconcave shape of erythrocytes increases their surface area for gas exchange, further enhancing their efficiency in oxygen transport.

The other components mentioned do not have this function. Platelets are primarily involved in blood clotting and do not play a role in oxygen transport. Plasma is the liquid component of blood that carries cells, nutrients, hormones, and waste products, but does not bind oxygen. Leukocytes, or white blood cells, are involved in the immune response and defense against infections, but are not involved in oxygen transport either.