Final answer:
The Native American nation with abundant food sources throughout the year, thanks to their rich natural environment, were the peoples of the Pacific Northwest.
Step-by-step explanation:
The Native American nation that had abundant food sources, even through the cold winter, due to their environment rich in heavy woodlands, freshwater lakes, and coastal access, were the peoples of the Pacific Northwest. These groups, including the Tlingit, Penutian, Chinook, and others, were adept at utilizing the abundant marine life and natural resources that their region had to offer. They fished for salmon, hunted various game, and collected shellfish, which, alongside the rich plant life, provided them with a stable and diverse diet. These tribes built permanent villages and had well-developed social structures, which allowed them to thrive in a region with a high carrying capacity of the land, even during harsh winter months.