There is less rainfall in the desert. Temperatures vary more in the desert. There is less water vapor in the desert air. There are fewer plants in the desert.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Why does a town in the desert rarely experience early morning fog as compared to a town along the coast?
Possibilities:
- There is less rainfall in the desert.
- Temperatures vary more in the desert.
- There is less water vapor in the desert air.
- There are fewer plants in the desert.

There is less water vapor in the desert air.