What is the hydrosphere?

• A. The layer of gases that surrounds Earth; includes air and weather.
• B. All solid parts of Earth, including rocks, soil, and landforms.
• C. All the water on Earth, including oceans, lakes, rivers, and groundwater.
• D. All frozen water on Earth, such as glaciers, ice caps, and permafrost.

Answer: (C)

The hydrosphere is the Earth's all-water system, containing oceans, lakes, rivers, groundwater, and other bodies of liquid water. It’s the part of the planet that holds and moves water across the surface and beneath it, interacting with the atmosphere and the solid Earth. The option describing all the water on Earth best captures this broad scope, since it includes oceans, lakes, rivers, and groundwater. The other choices point to different parts of the Earth system: the gaseous layer surrounding Earth is the atmosphere; all solid parts refer to the lithosphere; and frozen water like glaciers and ice caps are the cryosphere, which is only a subset of water on Earth.