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.
1996
1975
2017
2019
2020
2014
1967
1997
2023
1953
2021
1968
1976
1989
2009
1964