Answer:
A - Native Americans in New England were not very numerous but they had a healthy population level.
B - Several European explorers (and their crews) began to explore the area in the sixteenth century. These Europeans had contact with Native Americans and spread Eurasian diseases like smallpox to them.
C - Native Americans did not have antibodies for these Eurisian diseases, and the vast majority of them perished because of them.
D - When the Pilgrims arrived in 1620, the Native American population was minimal.