Answer:
Old people and owls are said to be this.
Tomorrow's yesterday. Yesterday's tomorrow. What is it?
I'm a starchy plant tuber that is one of the most important food crops, cooked and eaten fried, such as french fries.
Mary's child slept in one of these
You can't keep this until you have given it. What is it?
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.