Answer: the treaty of non-aggression
Explanation:
As a result of the Boxer Rebellion, China was subjected to even greater humiliation. ... Overwhelmed by the Western military response, the Chinese were humiliated by having to pay reparations and allow concessions to the Western powers that effectively denied them control over their own country.
U.S production plummeted
U.S inventors didn't have enough money to invent
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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.