Question

What is a phenomenon characterized by poorly planned development on the edges of cities and towns.

Answer 1

They're most likely referring to urban sprawl, which is usually associated with rapid, less thoughtfully planned development. 

It's usually thought of in a negative light, because the neighborhoods that develop lack the amenities, infrastructure, and/or identity of traditional neighborhoods. And because they're on the edges of cities, everyone usually relies on cars, which leads to traffic jams, pollution, and a lack of sense of community. 

Answer 2

Answer should be "Urban Sprawl" :DD