Six great confusions still unresolved

1. At a movie theatre, which 'arm rest' is yours?

2. In the word scent, is "S"  silent or "C"? 

3. If people evolve from monkeys, why are monkeys still around?    

4. Why is there a 'D' in fridge, but not in refrigerator?    

5. Who knew what time it was when the first clock was made?

6. If pro and con are opposites, wouldn't the opposite of progress be... congress?