I think the answer is either A or B
I believe the answer is smallpox, but I could be mistaken. There were lots of viruses threatening the population at the time but from what I know, smallpox was the largest threat.
The phrase "manifest destiny" is most often associated with the territorial expansion of the United States from 1812<span> to </span>1860<span>. This era, from the end of the War of </span>1812<span> to the beginning of the American Civil War, has been called the "age of manifest destiny".</span>
<span>Advanced mathematics was critical to the development of the Mayan calendar. The Maya needed a system of mathematics to record celestial movements over the years, to handle large numbers, and to calculate the solar and lunar year with great precision.</span>
