33. A. Improved mental functioning C. Speeding up of blood circulation 　　B. Increased susceptibility to disease D. Reduction of stress-related hormones

52. 　　What is crucial is recognizing that sustainable agriculture is not just about sustainable food production. 　　How do people ofen measure progress in agriculture? 　　(A) By its productivity (C) By its impact on the environmet 　　(B) By its sustainability (D) By its contribution to economic growth