Which statements describe magnetic poles? Check all that apply.

1. A north pole can exist without a south pole.
2. A north pole must exist with a south pole.
3. Two south poles placed near each other will repel each other.
4. Two north poles placed near each other will attract each other.
5. A north pole and a south pole placed near each other will attract each other.
6. A south pole and a north pole placed near each other will repel each other.