GRE Text Completion: Fundamental 24 Sets-GRE填空基础24套 - T527HVE1IBPXMSST!

Because insect communities serve as a sort of barometer, (i)____________ conditions in their (ii)____________, an entomologist's analysis of the insect species in a handful of soil can reveal much about the ecosystem. A. preserving B. environment C. stabilizing D. range E. registering F. destination