Answer: Cooling Earth's surface during the day.
Reflecting the sun's rays
Step-by-step explanation:
The formation of cloud is an integral part of the water cycle. When the water evaporates from the hydrosphere as well as from the biosphere the these vapours accumulate in the sky and condense to form clouds. The clouds are reservoirs for precipitation and makes the environment cool during hot summers.
Also the dense clouds are responsible for reflecting the direct incident rays on the biosphere as well as on the hydrosphere. Therefore, helps in maintaining the temperature of biosphere and hydrosphere cool.