Short Riddles and Answers

Question: Without one or the other both would not exist. what i'm I ?

Question: You are locked in a car and have a hammer. How do you get out?

Question: i am boiling hot and freezing col at the same time what am i?

Question: I am dark and can never be light, but I can be lit. What am i?

Question: What's the only school where you have to drop out to graduate?