Write the best brief argument you can to justify each of the following claims to someone who does not believe them.
1. Nine is not a prime number.
2. Seven is a prime number.
3. A molecule of water has three atoms in it.
4. Water is not made up of carbon.
5. The U.S. president lives in Washington, D.C.
6. The Earth is not flat.
7. Humans have walked on the moon.
8. Most bicycles have two wheels.