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.
2014
2004
2017
1927
2024
1967
1948
2005
2015
2020
2002
2019
2018
1958
1972
1950