Describes the unique features of Mars, its place in the solar system, its makeup, its satellites, and how scientists have learned about Mars through space missions or other research.
An introduction to weather that explains what weather is, how it works, what causes storms and snow, how the water cycle influences weather, and other related topics.
Describes the life cycle of the hippopotamus, including physical characteristics, habitat, diet, and dangers. Discusses their relationship with humans and the possibility that hippos might become endangered.
