When studying the calumet region of illinois and indiana, alfred meyer noted four stages of development as new groups occupied this land. in stage 4, new cities spread across new territory and grew toward one another

When studying the Calumet region of Illinois and Indiana, Alfred Meyer noted four stages of development as new groups occupied this land. In Stage 4, CONURBANIZATION, new cities spread across new territory and grew toward one another.

Alfred Meyer's sequence of population events:
1) Fur Trading Stage (up to 1830)
2) Subsistence Agriculture Stage (1830 - 1850)
3) Commercial Agriculture Stage (1850 -1900)
4) Conurbanization Stage (1900 - 1953) 

Answer (d) the greenhouse effect is primarily caused by car and trucks;