The blood component that has the greatest affinity for oxygen is the?

Step 1: Analyze the question The question asks which blood component binds oxygen most strongly, meaning which one carries oxygen.

Step 2: Explain the concept Blood has four main components, each with a different job:

• Erythrocytes (red blood cells): contain haemoglobin, a pigment that binds oxygen to form oxyhaemoglobin. They carry oxygen from the lungs to the tissues.
• Leucocytes (white blood cells): defend the body against infection.
• Lymphocytes: a type of leucocyte that produces antibodies and takes part in immunity.
• Thrombocytes (platelets): help blood clot at wounds.

Step 3: Work through the options

• A. Lymphocytes: immune function, no oxygen transport. ❌
• B. Leucocytes: fight disease, no oxygen transport. ❌
• C. Erythrocytes: contain haemoglobin, which has a high affinity for oxygen. ✅
• D. Thrombocytes: clotting only. ❌

Step 4: Answer The correct answer is C. erythrocytes.

Tip: Remember that erythro means red, so erythrocytes are the red cells, and red haemoglobin carries oxygen. You can also remember it as "Red cells = Respiratory gas carriers", while white cells are the "soldiers" and platelets are the "plasters".