text: This link should help I used this websites for my environmental science class when I had to answer the same question...\n\nGood Luck\n\nhttp://www.imagiverse.org/questions/archives/earth_science1.htm#QUESTION_11\n\nhttp://www.epa.gov/glnpo/monitoring/great_minds_great_lakes/history/come_from.html\n\n\nI really enjoyed helping because I learned some things myself!!\n\nGood Luck\nhttp://www.state.me.us/doc/nrimc/mgs/explore/geography/#q5