TOEFL Reading: ETS-TOEFL阅读机经 - B3P7F689V7C6DY1UL$

Accordingto paragraph 1, what was one result of the farming systems developed in river deltas in the Near East? A. There was a large increase in the overall amount of food produced. B. Large pools of labor became available to perform administrative tasks. C. The soil in these deltas grew much richer. D. The number of farming villages surrounding cities increased.