Answer:
The Native people in 1600 lived primarily in what is today the United States.
Step-by-step explanation:
A is correct because the population of Native people in what is today the United States greatly surpasses the population in what is today Canada, and this has been due to better living conditions, such as climate, water supplies, fertile soil...
B is not correct because Canada's population of Native people has been significantly smaller, and this has been mostly because of the harsher living conditions.