Answer:
The theory of Continental Drift
Explanation:
The theory of continental drift was proposed at the beginning of the last century by German scientist Alfred Wegener. Before Wegener developed his theory, it was thought that mountains formed because the Earth was cooling down, and, as it cooled down, it contracted.
Read more here: https://www(.)bbc(.)co(.)uk/bitesize/guides/z2q6cwx/revision/2#:~:text=The%20theory%20of%20continental%20drift,it%20cooled%20down%2C%20it%20contracted%20. *remove the parenthesis*
