Answer:
"where crests and troughs have their maxima at the same time"
Crests and troughs are 180 deg out of phase and when they have their maxima at the same time and place, their net contribution will be zero"
I'm pretty sure it is true. (78% sure)
It depends. If you are driving and the person doesn't look like a serial killer, you should stop.
Explanation:
The uneven heating causes temperature differences, which in turn cause air currents (wind) to develop, which then move heat from where there is more heat (higher temperatures) to where there is less heat (lower temperatures). The atmosphere thus becomes a giant "heat engine", continuously driven by the sun.
Wind is the result of pressure changes in the atmosphere due to temperature.
