What has many keys but can't open a single lock?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

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

What's the only room from which no one can enter or leave?

What is the only question you can't answer yes too?

What's not alive but can die?

What is black when it's clean and white when it's dirty?

What has an eye but can not see?

Who has 13 hearts but no organs?

What has teeth but Cannot bite?

What has a bottom at the top?

What has a neck but no head?