A、By staying in their animal skin houses. B、By making their homes facing south. C、By bathing themselves in the sun. D、By burning

M: Hey, Jane. What’ s so interesting?
W: What? Oh, hi, Tom.  I’ m reading this fascinating article on the societies of the Ice Age.
M: The Ice Age? There weren’t any societies then, just groups of cave people.
W: That’ s what people used to think. But a new exhibition at the American Museum of National History shows that Ice Age people were surprisingly advanced.
M: Oh, really? In what way?
W: Well, Ice Age people were the inventors of languages, art and music as we know it, And they didn’ t live in caves.  They built their own shelters.
M: What did they use to build them? The cold weather would have killed almost all of the trees, so they couldn’ t have used wood.
W: In some warmer climates, they did build houses of wood.  In other places, they used animal bones and skins or lived in natural stone shelters.
M: How did they stay warm? Animal skin walls don’t sound very sturdy.
W: Well, it says here, that in the early Ice Age, they often faced their homes towards the south to take advantage of the sun.
M: Hey, that’ s pretty smart ! I guess I spoke too soon.  Can I read that magazine article after you’ re done?
W: No problem.