- The cellular element in the blood primarily responsible for oxygen transport is the red blood cells.
- Red blood cells contain a protein called hemoglobin, which has a high affinity for oxygen.
- Hemoglobin binds oxygen molecules in the lungs and carries them through the bloodstream to tissues and organs, where oxygen is released to support cellular respiration.

- Platelets are involved in blood clotting rather than oxygen transport.
- Plasma is the liquid component of blood that carries nutrients, hormones, and waste products but does not transport oxygen directly.
- White blood cells are part of the immune system and are responsible for defending the body against infections, not oxygen transport.

Therefore, the primary function of oxygen transport is performed by red blood cells due to their unique hemoglobin content and structure.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th Edition, Chapter 41: Transport of Oxygen and Carbon Dioxide in the Blood