Answer:
How do you discover something that does not exist?
There are two sisters: one gives birth to the other and she, in turn, gives birth to the first. Who are the two sisters?
No matter how terrible things get for the people of the Arctic, they will not eat a penguin. Why not?
Which bank is not used for storing money?
How can you add eight 6s together so that the total adds up to 750?
A red house is made out of red bricks. A blue house is made out of blue bricks. What is a green house made out of?