Answer:
What starts with a P, ends with an E and has a million letters in it?
What goes up but never comes down?
What is the center of gravity?
If you drop me I'm sure to crack. But give me a smile and I'll always smile back.
What breaks in the water but never on land?
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.