III.    Complete the passage with the correct form of the words in brackets.

Over 8,300 plant species and 7,200 animal species around the globe are threatened with (1) __________ (extinct), and many thousands more become extinct each year before (2)__________ (biology) can identify them. The primary causes of species extinction or (3) __________(endanger) are habitat (4) __________ (destroy), commercial (5) __________(exploit) (such as plant collecting, hunting, and trade in animal parts), damage caused by nonnative plants and animals introduced into an area, and (6) __________(pollute). Of these causes, direct habitat destruction threatens the greatest number of species. Since the 1600s, the rate of extinction has accelerated (7) __________(rapid) because of human population (8) __________ (grow) and human resource (9) _________ (consu me). Many biologists believe that we are in the middle of the greatest mass extinction episode since the (10) __________ (appear) of the dinosaurs 65 mi llion years ago.

Over 8,300 plant species and 7,200 animal species around the globe are threatened with (1) __________ (extinct),