Answer:
It's in your hand though you cannot feel it. Only you and time can reveal it.
Old people and owls are said to be this.
What gets wetter and wetter the more it dries?
It keeps you on the ground and stops things from floating around. What is it?
An appropriately loud response to fear, excitement, or your team scoring.
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.