Answer:
They are Dark, and always on the run. without the sun, would be none!
A mechanism to discover who is following you.
Come up and we go, Go down and we stay.
It goes up and down the stairs without moving.
When I type I tap these on the keys
What is big and yellow and comes in the morning, to brighten mom's day?
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?