Easy
Actually the Greenback Party recommended the paper money. But in the given options the easy money refers to a money that could be easily regulated. Other forms of money such as gold coins cannot be regulated easily. A small amount of loss can result a huge turmoil while in the form of paper money it is just an alternative to the real assets. Paper money can be replaced by other notes if the previous notes are torn and damaged where the actual assets are not disturbed.
DNA, by taking the <span>evidence samples and dividing them soon after they're are collected, that way if a mix-up were to happen there would be backup samples to analyze.</span>
C) after the death of Kublai Khan, when the Chinese peasants revolted