Answer:
Their system of mathematics.
Explanation:
The Maya discovered zero. Most of the world's civilizations had no concept of zero at the time of the Mayans. Without zero there would be: No algebra, no arithmetic, no decimal, no accounts, no physical quantity to measure, no boundary between negative and positive numbers, and no computers. The Mayan’s discovery of zero was one of the most significant steps to get to where we are today.
The counting system was so simple. The Mayans figured out a genius system of counting which only required three symbols, a dot, a line, and a shell. These three symbols could be used in various combinations to keep track of the calendar and do arithmetic. Even the most uneducated people could use it to do basic trade.
There are many possible answers for this one! Only the national government can e.g. manage foreign relations, declare war or oversee trade between states and with other countries.
I think it's B. the period when the Roman Empire experienced peace and prosperity
