Answer:
What do you call the mother-in-law of your sister's husband?
Rotten trees and Jack-O-Lanterns have this characteristic in common.
What is yours but only used by others?
What calls for help, when written in capital letters, is the same forwards, backwards and upside down?
What falls down but is never injured?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.