Best riddles for teens

What happens when you throw a blue rock into the yellow sea?

You are on your way to visit your Grandma, who lives at the end of the valley. It's her anniversary, and you want to give her the cakes you've made. Between your house and her house, you have to cross 5 bridges, and as it goes in the land of make believe, there is a troll under every bridge! Each troll, quite rightly, insists that you pay a troll toll. Before you can cross their bridge, you have to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake. How many cakes do you have to leave home with to make sure that you arrive at Grandma's with exactly 2 cakes?

I’m at the beginning of the end and the start of eternity, at the end of time and space, in the middle of yesterday but nowhere in tomorrow. What am I?

I sleep when you are awake, I am awake when you fall asleep. I can fly but no feathers to aid my flight. What am I?

I don't have wings, but I can fly. I don't have eyes, but I will cry! What am I?

Everyone has it and no one can lose it, what is it?

There was a plane crash every single person died. Who survived?

Imagine you're in a room that is filling with water. There are no windows or doors. How do you get out?

I have keys but no locks. I have a space but no room. You can enter, but can't go outside. What am I?

If you have me, you want to share me. If you share me, you haven't got me. What am I?