Answer:
Big as a saucepan, deep as a cup, Even a river can't fill it up. What is it
Without this, H2O would just be 2O
It carries paper of the most important sort but also plastic, I'm glad to report. What is it?
There is 10 birds on a branch, a man shot 5 of them. How many were left?
They are two brothers. However much they run, they do not reach each other.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.