Five spheres, one planet
Scientists split Earth into spheres so they can talk about each part clearly. They still interact constantly — rain falls from the atmosphere into the hydrosphere, ice belongs to the cryosphere, plants in the biosphere grow in the geosphere.
Know the exact test wording
Hydrosphere = liquid water. Cryosphere = frozen water. Atmosphere = gases surrounding Earth. Geosphere = Earth's solid body. Biosphere = all living organisms. If two answers feel close, pick the wording that matches the definition list.
The 70% question
Water covers about 70% of Earth's surface. That water is the hydrosphere (oceans, mostly). Ice at the poles is extra — that is the cryosphere.