Answer: The atmosphere prevents the sudden increase in temperature during the daylight hours. And during the night, it slows down the escape of heat into outer space The atmosphere keeps the average temperature of the Earth fairly steady during the day and even during the course of the whole year.
I looked up your question just now and found this sight that has plenty of answers in it. https://www.britannica.com/place/Appalachian-Mountains
Hope this helps.
Yes it will help you with c and d