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"Some people were thus freed from the duty to produce their own food," (lines 15-16).

"But it took another huge leap in technology," (lines 16-17).

"thanks to other inventions, such as soap, medicines and sewerage." (lines 21-22)

"Moreover, the cities growing fastest today are not, … in the richer parts of the world." (lines 33-35)

"Only if the new cities of the developing world can find…" (lines 41-42).