What Am I Riddles

Question: Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.

Question: I am duplicate of you, but only lighter. What am I?

Question: Wind and cord combine, buzzing in the box. In all this we find, though to some the use is lost. What am I?

Question: What's higher than mountains, Smaller than trees?

Question: I hide when you wake but upset you as you sleep... What am I?