1. There are five types of blood cells.

2. The most common blood type is AB negative.

3. Too much manganese in the blood can be dangerous.

4. White blood cells outnumber red blood cells in the human body.

5. In the human body, blood flows because of pressure differences.

6. The capillaries are the thickest blood vessels.

7. A sphygmomanometer measures blood cholesterol levels.

8. In a blood-pressure reading, the numbers represent units of mercury.