Question

How was trade between america and europe countries affected by the war?

Answer 1

British and French demands for American goods created a trade imbalance

Answer 2

Which war?
If talking about the revolutionary war, it was because Britain had a lot of power and would try to keep other European countries from sending supplies to the U.S., one of the main European countries that traded with the U.S. during this time was France.

If you mean the World War it was because most of Europe was busy fighting and being conquered by Germany. The Germans wanted to cut off the trade with the U.S. because it would make them stronger.

I hope this helps.