Blood

This passage is about the four components of blood.

Lexile Level: 630L

Categories: Science & Technology

Do you have a two-liter bottle of soda in your refrigerator at home? That's how much blood your body makes every week. Most people think of blood as a liquid. However, doctors define it differently. They consider it a tissue, in the same way that your skin is. What we commonly call blood actually consists of four different things. Only one of them is a liquid. Red blood cells carry oxygen from the lungs to other parts of the body. They also collect waste so you can eliminate it. They are so numerous that they give blood its color. White blood cells are just as important though. They help fight disease and respond to foreign bodies like cancerous cells. Platelets are the component in your blood that form a scab when you have a cut. They respond within twenty seconds of an injury. They plug the hole. The liquid part of blood is actually a clear substance. It is called plasma.