Answer:
I'm a starchy plant tuber that is one of the most important food crops, cooked and eaten fried, such as french fries.
The day is their night and the night is their day, when I shout and they shout back I run away.
Cold head and feet; Round as a ball; Always turning around itself.
You walk into a room with a match, a kerosene lamp and a fireplace. Which do you light first?
This is your stomach's way of letting you know you've neglected it.
If it’s information you seek, come and see me. If it’s pairs of letters you need, I have consecutively three. What am I?