Introduces holes and the many ways they are useful to us, as in scissors, flower pots, fish nets, tunnels, lace, keys, garden hoses, and computer cards.
Recounts five episodes from history when the introduction of new plants or plant products, from grains and spices to coal, influenced the course of civilization.
Explains the importance of ears, hearing, and the sense of balance, and describes how we hear, how various animals hear, and how animal hearing differs in structure and usage from human hearing.
