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A. It requires mathematicians to work independently.
B. It is faced with many unprecedented challenges.
C. It lags behind other disciplines in collaboration.
D. It calls for more research funding to catch up.
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A. Scientists tried to send a balloon to Venus.
B. Scientists discovered water on Venus.
C. Scientists found Venus had atmosphere.
D. Scientists observed Venus from a space vehicle.
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A. It resembles Earth in many aspects.
B. It is the same as fiction has portrayed.
C. It is a paradise of romance for alien life.
D. It undergoes geological changes like Earth.
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A. It might have been hotter than it is today.
B. It might have been a cozy habitat for life.
C. It used to have more water than Earth.
D. It used to be covered with rainforests.
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A. Causes of sleeplessness.
B. Cross-cultural communication.
Cultural psychology.
D. Motivation and positive feelings.
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