Which component carries oxygen in the bloodstream?

Which component carries oxygen in the bloodstream?

• A. Red Blood Cells
• B. Plasma
• C. White Blood Cells
• D. Platelets

Answer: (A)

Red blood cells are the primary carriers of oxygen in the bloodstream. They contain hemoglobin, a protein with iron that binds oxygen in the lungs and releases it to tissues where it’s needed for cellular respiration. Hemoglobin can carry up to four oxygen molecules per molecule, and each red blood cell contains millions of hemoglobin molecules, making this the main mechanism for transporting oxygen throughout the body. The plasma can dissolve only a small amount of oxygen, so it contributes little to overall transport. White blood cells and platelets have other roles—immune defense and blood clotting—so they don’t function in oxygen transport. This is why red blood cells are the correct choice.

Red blood cells are the primary carriers of oxygen in the bloodstream. They contain hemoglobin, a protein with iron that binds oxygen in the lungs and releases it to tissues where it’s needed for cellular respiration. Hemoglobin can carry up to four oxygen molecules per molecule, and each red blood cell contains millions of hemoglobin molecules, making this the main mechanism for transporting oxygen throughout the body. The plasma can dissolve only a small amount of oxygen, so it contributes little to overall transport. White blood cells and platelets have other roles—immune defense and blood clotting—so they don’t function in oxygen transport. This is why red blood cells are the correct choice.