Simple riddles for teens with simple answers

I am pronounced as a one letter alphabet. I am written with three letters. I am complete with just two letters. I am double. I am blue I am black I am brown I am gray I am yellow and I am green. I can read from both ends. I appear the same every way! What am I?

My life can be measured in hours. I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.

Born of water, I drown in water. A blood-thirsty beast you can barely see. What am I?

Why is a river rich?

Never trust this fellow’s grin. His teeth are sharp and course, his blood’s as cold as icicles, and he’ll show no remorse! What is it?

If will follow you for 1000 miles but not miss home. It desires neither food nor flowers. It fears not water, fire, knives, nor soldiers. But it disappears when the sun sets behind the western mountains. Who Am I?

This very thing you were born with pleases us all. It's even capable of making men fall, while only experienced by few it's treasured by all.

A mirror for the famous, but informative to all. I'll show you the world, but it may be a bit small. What am I?

What body part is pronounced as one letter but written with three, only two different letters are used?

Galaxy Detective Karamchand was on a case. A spaceship was lost. Her partner, Galaxy Junior Detective Brightstar gave her a piece of paper. This was the location of the spaceship! This is what the slip had scribbled on it: Juice, Umbrella, Potato, Ice, Tomato, Elephant, Rice. Where is the spaceship?