What makes jurassic time period unique

Im only a 6th grader but im trying: That it was the only period with dinosaurs alive, right before a asteroid hit it 

Yeah that was before the astroid so the dinosaurs were alive plus think of Jurassic Park

Master planned communities outside of chicago. note: population density means people living in an area per square mile. chicago, an urban and highly populated area has a much more higher density than a desert, amish community, settlement, or nomadic region.

Answergoogle earth; i believe this is the correct answer, plz check first;