Answer:
I transfer oxygen from the atmosphere to your blood
Draw fire or fill me; I'm still empty.
I am in the past, never in the future. I don't exist, but have existed. I saw what you saw, and this is what I will ever see. What am I?
I have feet on my head
What kind of room has no doors or windows?
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard. Who am I?