Review
A system is a group of parts that work together.
Earth is a system because it has different parts that interact and work together - the hydrosphere, biosphere, atmosphere, and geosphere.
Hydrosphere - all of the liquid water and ice Earth
Biosphere - all the living things on Earth
Atmosphere - the air that surrounds Earth
Geosphere - the solid part of Earth
For each example, choose if this is part of the hydrosphere, biosphere, atmosphere or geosphere.