Precipitation occurs when

a. it's warm and moist outside

b. cloud droplets get too heavy and fall

c. water vapor cools and condenses

d. it's dry and cold outside

The correct answer is C. Water vapor cools and condenses. Depending on the rest of the climate, this can either result in rains falling, sometimes even serious monsoons, or it can end in snow and hail which can be extremely dangerous for agriculture and cost countries millions of dollars of failed produce.

Its either a) or b),wind and water erosion gradually widen the canyon

The awnser is b i believe