Blood is made up of four main components: plasma, red blood cells (RBCs), white blood cells (WBCs), and platelets. Plasma is the liquid part that carries nutrients, hormones, and waste. RBCs transport oxygen, WBCs fight infections, and platelets help in clotting. Together, they maintain balance, immunity, and oxygen flow in the body.

Key Points to Know

• Plasma: 55% of blood; mainly water and proteins.
• Formed elements: RBCs, WBCs, and platelets.
• Function: Transport, defense, and regulation.