This document is a PowerPoint presentation about blood cells submitted by Anusree.C to her lecturer Smt.Soya.P. It introduces the three main types of blood cells - red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Red blood cells transport oxygen in the blood and have a biconcave shape for increased surface area. White blood cells protect the body from infection and include neutrophils, eosinophils, basophils, lymphocytes and monocytes. Platelets are cell fragments that help the blood clotting process by gathering at injury sites to form clots and prevent blood loss.