Blood | Science Trek
![blood plateletes in a blood vessel](https://wpsu.psu.edu/wp-content/uploads/2022/01/science-trek-blood.jpeg)
This video segment from IdahoPTV’s Science Trek defines the 4 parts of blood and shows the rest of the circulatory system. Discover where blood is made, how long a blood cell lives, what blood types are, why blood is red, and what a transfusion is.