Because there are no habitable planets other than Earth in our solar system and because it is unlikely we will ever have the capability to reach other systems, the conclusion that humankind will never colonize outer space seems justified. Consider, however, that every planet lies at the bottom of a deep gravity well. It not only takes energy to lift people and material out of such wells; it also takes considerable energy to lower them to the bottom in good working condition. Human beings need air, water, and food, but we need not continue to supply ourselves with these necessities under such inefficient conditions. The asteroid belt between Mars and Jupiter contains billions of tons of the ices of water, ammonia, and carbon dioxide, everything needed to provide food, air, and water, as well as abundant metals from which to build shelter. And relatively little energy would be required to exploit those vast resources because the asteroids, having little mass individually, do not lie at the bottoms of deep gravity wells. Therefore, human beings do not need to live on planets.
Which of the following statements, if true, would most weaken the conclusion drawn in the passage above?
A) Most human beings are physically unable to withstand acceleration out of gravity wells.
B) Minute amounts of trace elements available only on Earth are required for human subsistence.
C) Human beings are physiologically unable to develop and function properly outside the confines of a strong gravity field.
D) Given current technology, it would take more than eight years to complete a round trip from Earth to the asteroid belt and back.
E)The resources of asteroids are more likely to be exploited by the descendants of colonists from Earth.
Because there are no habitable planets other than Earth in our solar system and because it is unlikely we will ever have
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