The decline of the Mound Builders of Cahokia brought a mass exodus caused by resource shortage.
Answer: Option 4
<u>Explanation:</u>
Mound Builders were a group of people lived in a place called Cahokia. They built various styles of mounds to live in, to worship and also to bury people. Cahokia flourished well and their major production was corn. Also, it reformed to a notable successful city by other cities.
During the 13th century, the medieval climate warming started to happen. According to researches Cahokia had experienced a prolonged drought in its 1350s. Also, the land became unsuitable to grow corns. The food resources also started to reduce in the area.
All the resources were more scarce after 1250. So people started o leave the place abandoned to new places they could survive. At the time of Spanish's entry to Cahokia in the 15th century, the place was completely abandoned.
