White blood cells are known as

• A. Leukocytes
• B. Erythrocytes
• C. Platelets
• D. Hemoglobins

Answer: (A)

White blood cells are immune system cells called leukocytes. They defend the body against infections and foreign invaders, and they contain a nucleus, unlike mature red blood cells. The term erythrocytes refers to red blood cells, which carry oxygen thanks to hemoglobin. Platelets are small fragments that help blood clot. Hemoglobins describe the oxygen-carrying protein inside red blood cells, not a cell type. So, the correct term for white blood cells is leukocytes, encompassing the various immune system cell types such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils.