Video narration
If blood is one red liquid, how can it do so many jobs? Think of it as a school team moving through your body. It is not one kind of worker doing everything; different members have different jobs. RBCs are delivery workers. They carry oxygen around your body, taking this supply to your tissues. WBCs are security guards. Unlike RBCs, they help defend you against disease-causing germs. Platelets are repair workers. When you get a cut, they gather at the wound and help form a clot, like a quick plug that reduces blood loss. So blood works because its team works together: delivery, defense, and repair. Healthy blood needs different components doing different jobs. How can one red liquid do so much? RBCs deliver oxygen, WBCs fight germs, and platelets plug wounds-three team jobs that keep your body working.