In one theory, what led humans to move north into Europe?

Hey there! It looks like you've asked a multiple choice question without providing your answer choices. Don't fret I've found them. They are:

A) An Ice Age started and the planet got colder.

B) An Ice Age ended and the planet warmed up.

C) Humans were starving and needed more food.

D) Humans invented boats and could sail to Europe.

The correct answer is B. As the planet got warmer people wanted to move further north.