A recent survey found that the two environmental issue of greatest concern to the average American are the rate at (31)_________land is being developed and places in nature are being lost, and the loss of rain forests. Almost 70 percent of the people (32)_________strongly agreed with the statement: “We have a personal responsibility to the earth to protect all plant and animal life.” In (33)_________study by the American Museum of Natural History, 70 percent of scientists interviewed said they believe that during the next thirty years as many as one-fifth of all species alive today will (34)_________extinct. A third of the respondents think as many as half of species on Earth will die out in that time. Most of the scientists agree that human (35)_________is the main cause of the problem. Factors such as expanding human settlements, logging, mining, agriculture, and pollution contribute towards destruction of ecosystems, and species extinction. 31. A. who B. which C. what D. that 32. A. surveyed B. questioned C. talked D. studied 33. A. other B. others C. another D. the other 34. A. become B. come C. get D. begin 35. A. act B. action C. acting D. activity