A young boy learns about his heart through the step-by-step construction of a simple circulatory system. He learns how his heart pumps, what blood and blood vessels do, how they do it, and some of the ways to help his heart stay healthy.
2010
1984
2021
1898
2005
1989
2008
2017
2018
2002
1960
2014
2022
2001
2012
2011
2016
1962