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.
2016
1968
1973
2000
2025
2020
1956
1959
1961
2022
2018
2023
1964
1955
2024
1966
2015
1934