What early human development was necessary for survival in cold environments?

finding shelter in caves
banding together in clan groups
wearing wool clothing for warmth
creating language to communicate

Strong boddies adapted to cold climates.

When early humans spread to colder climates, their body shapes evolved in ways that helped them stay warm. Short, wide bodies conserved heat. Early humans continued to depend on both raw meat and cooked food, both of which could be efficiently processed in a short digestive tract.

I am sorry if this doesn't answer your question, but this was the only answer I could find...

a drastic rise in oil prices ended decades of postwar.

not sure but thinking i'ts cause the government was broke. not sure