I think the person in the top chose it randomly for points so it probably wrong !
Answer:
Urban areas doubled, tripled, or quadrupled in size which led to over crowding in cities. Sometimes a large population is a good thing, but in this case the population was too big and caused many health problems.
Explanation:
I believe that the answer is negative space.
Before pumpkins people carved lots of vegetables turnips, potatoes and squashes/gourds into Jack O Lanterns.
