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.
1959
2002
2024
1968
2007
1933
2009
1975
2016
2023
1895
2015
1980
1976
1896
2005
2003
1966