Answer:
Because ww1 ended.
Explanation:
I don’t know. That makes the most sense to me.
One current theory is that trade with Mesopotamia (which was very important to the Indus Valley civilization) slowed or stopped, due to Mesopotamia's own troubles at the time.
Overestimate one’s capabilities, to be overly confident is harmful
Great Britain began stopping American sea vessels and into the vessels on the military subjects
