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.
1953
1957
1968
1965
1981
2020
1894
1972
2002
1921
1987
1993
2018
2005
2021
1988
1976
1967
1925