In the water cycle, clouds form as a result of

Condensation is the process by which water vapor in the air is changed into liquid water. Condensation is crucial to the water cycle because it is responsible for the formation of clouds. ... Water molecules in the vapor form are arranged more randomly than in liquid water.

Explanation:

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

c. establishing proper sleep hygiene