Anthropologist Michael Heckenberger Found Evidence That Human Settlements Had Much

Anthropologist Michael Heckenberger found evidence that human settlements had much larger populations in parts of the Amazon rainforest earlier than was previously believed. His research suggests which of the following:

A) unlike more customary understandings of Amazon-dwelling people, they have been cultivating the rainforest for much longer than previously assumed
B) unlike similar early farmers and even hunter-gatherers Amazonian people were engaged in wide-ranging trade networks
C) unlike what we previously assumed, these Amazonian people subsisted on far fewer calories than people do today
D) all of the above.