The Digestive System

by Alvin Silverstein

Published 31 December 1970
Briefly discusses the various ways plants and animals obtain and utilize food, describes the human digestive system and what happens to a roast beef sandwich when it is eaten, and explains the principles of nutrition.

The Reproductive System

by Alvin Silverstein

Published 31 December 1971
Explores the mating habits and reproductive process of several members of the plant and animal kingdoms.

The Endocrine System

by Alvin Silverstein

Published 31 December 1971