Answer:
I may seem real but it always turns out I was never there in the first place... you only see me during a certain resting stage.
What can fill a room but takes up no space?
I lose my head in the morning and regain back it at night.
Draw fire or fill me; I'm still empty.
What is made of wood, but can't be sawed?
Lynn likes grapes but not potatoes. She likes squash but not lettuce, and she likes peas but not onions. Following the same rule, will she like pumpkins or apples?