Answer:
Feed me anything and I will live.. But feed me with water and I will die...
How do you discover something that does not exist?
On which day of the year do fewest people die?
When is homework not homework?
Is an older one-hundred dollar bill worth more than a newer one?
I appear in the morning. But am always there. You can never see me. Though I am everywhere. By night I am gone, though I sometimes never was. Nothing can defeat me. But I am easily gone.