The underground water and the water on the Earth’s surface together are called:

The total water present on Earth, including underground water (like aquifers and groundwater) and surface water (like rivers, lakes, and oceans), is collectively called the hydrosphere. The hydrosphere represents all the water in solid, liquid, and gaseous forms and covers approximately 71% of the Earth’s surface.

Groundwater is found beneath the Earth’s surface in soil pores and rock formations. It is a critical source of water for drinking, agriculture, and industry. Surface water includes rivers, lakes, and oceans, which play a vital role in supporting life, regulating climate, and providing resources for humans and ecosystems.

The other options are incorrect:

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  The mesosphere is a layer of the Earth’s atmosphere located above the stratosphere, unrelated to water.

  
  


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  The ionosphere is a part of the upper atmosphere containing charged particles, important for radio communication, but it is not related to the Earth’s water.

  
  

The concept of the hydrosphere is fundamental in Earth science, environmental studies, and geography, as it explains the movement and cycling of water through precipitation, rivers, oceans, evaporation, and groundwater recharge. The hydrosphere interacts closely with the lithosphere, atmosphere, and biosphere, forming a complex system known as the Earth system.

Understanding the hydrosphere is crucial for water resource management, climate studies, and conservation. It helps scientists predict floods, manage irrigation, and study global environmental changes.

In summary, the underground water and surface water together form the hydrosphere, encompassing all water on Earth and playing a central role in sustaining life and maintaining the planet’s natural balance.