52. How do people often measure progress in agriculture? (A) By its productivity (C) By its impact on the environment (B) By its sustainability (D) By its contribution to economic growth

56 What is the author’s purpose in writing this passage? (A) To remind people of the need of sustainable development (B) To suggest ways of ensuring sustainable food production (C) To advance new criteria for measuring farming progress (D) To urge people to rethink what sustainable agriculture is