wich city in the great lake area is busiest for shipping goods

A lengthy Google search has produced two answers -- Port of Indiana and Duluth, Minnesota.

Depending upon how you define "busiest for shipping goods," either answer may be correct.

http://72.14.209.104/search?q=cache:cLckULT6oEcJ:www.greatlakes.org/habitat/bio_recovery.asp+Great+Lakes+busiest+port&hl=en&gl=us&ct=clnk&cd=1&ie=UTF-8

http://www.britannica.com/ebi/article-9274077