1. D. Inca settlements were difficult to find and reach because they were build at high altitudes on rough terrain.
Inca civilizations were well hidden and protected from outside influences due to their location high in the Andes Mountains of South America. It took the Spanish a while to find them, though diseases reached the outlying settlements even when the Spanish did not.
2. D. infectious diseases and drought
The Maya civilization experienced a lengthy and extreme drought that led to widespread starvation, which reduced their population and influence over the region long before Europeans arrived in Mesoamerica. The Inca and the Aztec populations were wiped out by the infectious diseases the Spanish conquistadores brought with them.
I also just took the test and got it right
