Which cellular elements are present in blood?

The correct response highlights the primary cellular elements found in blood: erythrocytes, leukocytes, and platelets. Erythrocytes, commonly known as red blood cells, are responsible for transporting oxygen from the lungs to the tissues and facilitating the return of carbon dioxide to the lungs for exhalation. Leukocytes, or white blood cells, play a crucial role in the immune response, helping the body to fight infections and other diseases. Platelets are essential for blood clotting; they help prevent bleeding by aggregating at sites of injury to form clots.

Plasma, while a vital component of blood, is not a cellular element; it is the liquid portion that carries cells, nutrients, hormones, and waste products. Therefore, the inclusion of plasma in any answer option would not accurately reflect the cellular components of blood. The other options either omit essential cellular elements or incorrectly specify them, thus not providing a complete representation of what comprises the blood's cellular makeup.