Good Riddles

Question: What can you hear but not see?

Question: There were 2 men climbing on mount everest when one man falls off the edge, the next day both of the men have dinner together. How can this be?

Question: 5 men go skydiving but when they jump out of the plane, only 4 men have a parachute. How do they all survive?

Question: What has classes but moves?

Question: What didn't Adam and Eve have that everyone else has?