单项选择题

The sharp rise of the snow geese population is mainly caused by ______.

A．lack of natural enemies
B．great care of wildlife preservationists
C．favorable conditions in their winter habitat
D．changes in their migration patterns

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热门试题

单项选择题

The Chickscope Project enabled students to do all of the following EXCEPT ______.

A．to set up an incubator to hatch chicks
B．to actually operate an MRI system
C．to get involved in actual research
D．to watch the changes in the chick embryo

单项选择题

Judging by the passage, biologist David Anderson ______.

A．seemed to be interested in marathon
B．made use of a satellite in his research
C．was probably a specialist in remote education
D．put together multimedia presentations for NSF