Answer:
My life can be measured in hours. I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
What can you put in a barrel to make it lighter?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.
What goes with a car, comes with a car, is no use to a car but a car cannot move without it?
We are all around, yet to us you are half blind. Sunlight makes us invisible, and difficult to find
When is it bad luck to see a black cat?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?