Too many government regulations but I am not sure on the second answer
Answer:
They were following food during the Ice Age.
Explanation:
If you are talking about them trying to expand in to present-day Canada, then it brought renewed conflict with Britain (war of 1812)
if it is towards the west, i guess it hampered technological development, because most people were moving west through the trails, instead of staying to help build up the economy
hope this helps
the devastation it experienced in World War II.
Flooding and silt should be the answer