Answer:
What loses its head in the morning but gets it back at night?
I have a little pool with two layers of wall around it. One white and soft and the other dark and hard. Amidst a light brown grassy lawn with an outline of a green grass.
I have cities without people forests without trees and oceans without water. What am I?
I begin and have no end. Eventually, I will be the ending of all that has begun. What am I?
I break down buildings, I crumble mountains but you can't see me. What am I?
No matter how little or how much you use me, you change me every month.