Indefinite Pronouns

45 -It is implied that European climbers first started climbing mountains outside Europe ---.

A) because the Alps in Europe took far too long to climb

B) once they had been inspired by Albert Smith's lectures

C) in order to obtain the sizeable financial benefits on offer

D) so that they could make field maps of other areas

E) as they wanted to climb previously unclimbed mountains

Fossil analysis reveals that at least five periods in the last 600 million years have seen a drastic reduction in the number of species of flora and fauna on the Earth. However, on previous occasions such changes were brought about by asteroids or dramatic climatic changes. Experts in general believe that this decline is the work of man. The dominance of a single species type, homo sapiens, threatens to turn the rest of the living 'world upside down. With a population of barely six billion, humans are rapidly destroying irreplaceable ecosystems. This sixth round of global dying of species could be far larger than the first five.

46 -According to the passage, the dominant belief among scientists is that ---- .

A) throughout history there have been periods when many species of life have become extinct

B) the present climatic change known as global warming is probably a natural phenomenon

C) the Earth is in danger of being struck by an asteroid

D) the present decline in the number of species is caused by the activities of mankind

E) we are experiencing the fifth period of species dying out