Answer:
The part of the bird, that is not in the sky, Which can swim in the ocean and always stay dry. What is it?
A person's greatest asset.
What has to be broken before you can use it?
Humans have two that shrink in the light and expand in the dark
What ship has no captain but two mates?
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.