why number 8549176320 is one of a kind?

I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?

Can it be possible to build a house that has all its four walls facing towards the South?

Can you name some countries which do not have the alphabet 'A' in them?

What makes this number unique: 8,549,176,320?

Why are televisions attracted to people?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

Which alphabet letter is a question?

Which fur should we be getting from the Lion?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?