Best short riddles for teens

What's round and bad-tempered?

There are different types of stones available. However, there is one type of stone you cannot find in the ocean! What is that?

What do you throw out when you want to use it, but take in when you don't want to use it?

Find three positive whole numbers that have the same answer added together or when multiplied together.

What did the boy bird say to the girl bird on Valentine's Day?

What type of cheese is made backwards?

I go around all the places, cities, towns and villages, but never come inside. What am I?

We hurt without moving. We poison without touching. We bear the truth and the lies. We are not to be judged by our size. What are we?

What has six faces, but does not wear makeup. It also has twenty-one eyes, but cannot see?

You see a boat filled with people. It has not sunk, but when you look again you don't see a single person on the boat. Why?