Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

What number should come in place of the question mark below?

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?

What breaks yet never falls, and what falls yet never breaks?

Who can jump higher than a Mountain?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

Why is a river so rich ?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

What is the probability of choosing the correct answer at random from the options below?

a) 1/4
b) 1/2
c) 1
d) 1/4

Rectify the following equality 101 - 102 = 1 by moving just one digit.