Question 76

Water enters atmosphere by evaporation.

Water enters the atmosphere primarily through the process of evaporation, where liquid water is transformed into vapor due to heat from the sun.

A) Precipitation

Precipitation refers to water that falls from the atmosphere to the Earth's surface in forms such as rain, snow, sleet, or hail. While it is a crucial part of the water cycle, it does not describe the process by which water enters the atmosphere.

B) Evaporation

Evaporation is the correct choice as it describes the process where water from oceans, lakes, rivers, and other bodies of water is heated by the sun and changes into water vapor, thus entering the atmosphere.

C) Runoff

Runoff is the flow of water, usually from precipitation, over the land surface and into bodies of water. It is a process that occurs after precipitation, not a mechanism by which water enters the atmosphere.

D) Erosion

Erosion is the process of the wearing away of the Earth's surface due to various factors such as water, wind, or ice. While it can lead to changes in water bodies, it does not facilitate the entry of water into the atmosphere.

Conclusion

Evaporation is the definitive process through which water transitions from a liquid state to vapor, thereby entering the atmosphere. All other options describe different aspects of the water cycle that do not pertain to the introduction of water into the atmospheric system. Thus, evaporation is the essential process being tested in this question.