Re: why is it that as we go up the mountain, the air becomes colder?

For your first question, there is a direct relationship between pressure and temperature. They are directly proportional, that is, as one increases, so does the other. As the altitude increases when traveling up a mountain, the air pressure decreases. Therefore, the temperature also decreases. This relationship is called the "gas laws" and information can be found in many places, including Gas Laws at Wikipedia.

For your second question, you might find the following Wikipedia site useful for a better explanation: Hydrologic Cycle at Wikipedia.

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