According to a study published in 2014, the skeletal remains of "naia", found in an underwater cave in the yucatán peninsula, give strong evidence for the notion that:

a. Water once covered the entirety of modern mexico and humans had adapted to these conditions

b. Members from one single, genetically uniform population populated the americas from at least 16,000 years ago

c. Early amerindian cultures practiced human sacrifice

d. Cro-magnon peoples had emigrated to the americas carried by favorable winds across the atlantic ocean

The remains of a teenage girl, aged 15-17 at her death, and nicknamed "Naia", that are more than 12,000 years old, were inside a flooded cave located near Tulum, Quintana Roo in Mexico. They were recovered in 2007 by the cavers Alejandro Álvarez, Alberto Nava and Franco Attolini, of the Tulum Speleological Project (PET), dedicated to the registry of the underwater heritage of the region. After seven years of research, a multidisciplinary team from USA, Canada and Mexico, whose principal investigator of the research on "Naia", James Chatters, an archaeologist and paleontologist, reported in 2014, that "Naia" has already contributed to understand the origins of the first Americans and her DNA confirms the idea that "a single group of Asian emigrants gave rise to both the earliest American settlers and modern Native Americans". So, right answer is B. Members from one single, genetically uniform population populated the Americas from at least 16,000 years ago.