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.
1976
2021
1999
2016
2003
2005
1996
1922
1961
2019
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2013
1956
2022
2024
2014