JAMB - Biology (2001 - No. 18)

White blood cells are also called leukocytes. They protect you against illness and disease. Think of white blood cells as your immunity cells.

Platelets, or thrombocytes, are small, colourless cell fragments in our blood that form clots and stop or prevent bleeding. Platelets are made in our bone marrow, the sponge-like tissue inside our bones.

Phagocytes are a type of white blood cell (leukocyte) that are part of the immune system's defense mechanism. 

Red blood cells (RBCs) transport oxygen from the lungs to the body's tissues. RBCs contain hemoglobin, a protein that binds to oxygen. The Red blood cells are also referred to as erythrocytes.