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.
1965
1968
2018
2024
1963
1985
2020
1910
1981
2025
2015
1974
2019
1979
2006
2002