Let's start with question 1...

"All nations are in debt"?
Norway, Kuwait, Qatar, Saudi, Iran, Macau, Brunei and about 30 other countries aren't in debt.

2 - who tests dog food? dogs, obviously.
3 - that's just stupid.
4 - the plane would be too heavy to get off the ground.
5 - UNESCO
6 - yes
7 - because some dogs traditionally worked hard
8 - because telephone keypads mimic the now outdated rotary dial systems, whereas keyboards are based on old cash registers.
9 - no
10 - metaphorically or literally?
11 - copacetic. A more interesting question is "what is the origin of the word Okay"
12 - same reason you don't fall out of bed when you are asleep.
13 - the color is generally believed to be named after the fruit.
14 - I assume that would depend on the nature of their amnesia, and the nature of their cure.
15 - ?
16 - yes.
17 - because English is not always logical.
18 - the short answer is no, because the sound waves travelling from the speakers to you would not be travelling as fast as your ears.
19 - assuming this were possible... since the light wouldn't be able to travel ahead of you and reflect back, you wouldn't even know that the lights had been switched on
20 - because in the olden days, a TV 'set' was a set - the screen, the FM received, the power supply etc, were all somewhat seperate, so the collection of appliances was considered a 'set'.
21 - depends on the jurisdiction
22 - to make you feel like you didn't waste all that money.