Blood

human body · circulatory system · biology

Body delivery service. Blood acts like a busy delivery truck, carrying oxygen and nutrients to all of your cells and hauling away waste they don't need.

Always on the move. Blood travels through your circulatory system, pushed along by your heart to reach every corner of your body.

Why it's red. Blood gets its red color from oxygen-carrying cells, and it's found in humans and other vertebrates, animals with backbones.

Waste cleanup crew. Besides delivering goodies, blood collects metabolic waste from your cells so your body can get rid of it.