Heart


Description:
The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system. <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Heart_anterior_exterior_view.jpg/1024px-Heart_anterior_exterior_view.jpg" width="500"> From [Wikipedia](https://en.wikipedia.org/wiki/Heart) under [CC BY-SA 2.5](https://creativecommons.org/licenses/by-sa/2.5) license.

Experiments: