环境的使用价值中OV是（）。
A、直接使用价值
B、间接使用价值
C、选择价值
参考答案：C
（）在阳离子H2S分组方案中，Ⅱ组离子包括Hg2+、Pb2+、As（Ⅲ）三种。
Why are the private lands surrounding Glacier National Park so important a. They function as a hunting preserve. b. They are restricted to government use. c. They are heavily populated. d. They contain natural habitats of threatened species.
