Answer:
It increases and decreases yet no one see it. It is not a fire and yet it can be quenched.
What becomes white when it is dirty?
A DJ does this to records. I do it to mosquito bites.
What do you get if you cross an apple with a Christmas tree?
How did Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune make up the solar system?
What is always coming but never arrives?