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.
1987
1930
1995
2021
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2014
1944
2012
2024
2022
1946
2020
1955
2018
2015
2025