The sphere of the Earth that contains the oceans and lakes is called the "hydrosphere." This layer encompasses all the water found on, under, and above the surface of the Earth. It includes not only oceans and lakes but also rivers, glaciers, groundwater, and vapor in the atmosphere. The hydrosphere covers about 71% of the Earth's surface, with the majority of this water found in the salty oceans. The hydrosphere plays a crucial role in supporting life, regulating climate, and influencing weather patterns. Its health is essential for ecosystem balance and human survival.