1. Forward I am heavy, but backward I am not. What am I?

2. What English word retains the same pronunciation, even after you take away four of its five letters?

3. What did the fish say when he ran into a concrete wall?

4. What English word can be written forward, backward or upside down, and can still be read from left to right?

5. What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?