Good Riddles

Question: I am unseen but all people know of me. I am intangible yet sharper than any sword. I come from nothingness but can fell even the mightiest kings.

Question: Most people are born on one, die on one, and experience some of their most blissful moments upon it.

Question: An iron horse with a tail of flax. The more the horse gallops, the longer his tail becomes.

Question: On 20 planes I may be, but only rest on one you see. I can help you or hurt you, depending on where I lay. Because I am not the kind you use everyday

Question: Imagine your in a sinking boat and there is alligators trying to eat you. How do you save yourself?