Good Riddles

Question:

What is the most common use of cowhides?

Question: I'm small but big, i hide behind you but come out when you fall... What am I?

Question: It takes 45minutes for a man to cross the brige onthe brige there is a security personel who doesn't allow people to cross the brige to either side but he sleeps for only 35minutes so there was a wise man who crossed the brige so how could he do it

Question: What room can you eat?

Question: There was once three trees. The first tree did whatever the third tree did, and the third tree did what ever the second one does. What happens if tree number two gets cut down?