Answer:
The last woman on Earth received a phone call. Who was the caller?
I am always around you but often forgotten. I am pure and clean most of the time, but occasionally rotten. What am I?
I go up and never come down no matter how hard you wish. As I get higher more wrinkles crawl onto your face.
I plow and plow, but never sow. What am I?
I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?
Give it food and it will live, give it water and it will die.