Read the excerpt from the article Skara Brae. The small, stone village was built some time around 3100 BCE. The first villagers dug down into an existing midden heap, or trash heap, to build the foundations of their homes. The garbage helped to insulate and protect the homes. They built their round huts with stones found locally, sticking each piece together with a paste made from ground-up waste and dung.

After the houses were built, the villagers furnished their homes with stone beds, one on each side of the door, a stone dresser, and a fireplace, or hearth. The hearth kept the home warm and allowed the inhabitants to cook their food.

What does the phrase helped to insulate suggest about the homes found in Skara Brae?

The people who lived in the village of Skara Brae enjoyed being outside in the winter months.
The people who lived in the village of Skara Brae enjoyed the smell of trash.
The weather was cold, so the people needed to build homes that kept the warmth inside.
The weather was not too cold, so people built their homes in garbage piles.