Answer:
The basin rests 282 feet below sea level, and lets in the hot sun to creep into the valley, while getting very little rain.
So I would say, the amount of precipitation or temperature has the biggest effect.
*I do not know for sure, I just took a shot at it
The answer is true because it helps you know where everything is and helps you do whatever your doing
I don't think so. if its too even and have no tilt, everything will be the same