Answer:
Soldiers fight it but never changes.
It carries paper of the most important sort but also plastic, I'm glad to report. What is it?
Old Mcdonald had this
How can you throw a ball as hard as you can, to only have it come back to you, even if it doesnβt bounce off anything?
What is all over a house?
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard. Who am I?