Which of the following most logically completes the argument below? Within the earth’s core, which is iron, pressure increases w

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问题 Which of the following most logically completes the argument below?
Within the earth’s core, which is iron, pressure increases with depth. Because the temperature at which iron melts increases with pressure, the inner core is solid and the outer core is molten. Physicists can determine the melting temperature of iron at any given pressure and the pressure for any given depth in the earth. Therefore, the actual temperature at the boundary of the earth’s outer and inner cores—the melting temperature of iron there—can be determined, since__________.

选项 A、the depth beneath the earth’s surface of the boundary between the outer and inner cores is known
B、some of the heat from the earth’s core flows to the surface of the earth
C、pressures within the earth’s outer core are much greater than pressures above the outer core
D、nowhere in the earth’s core can the temperature be measured directly
E、the temperatures within the earth’s inner core are higher than in the outer core

答案A

解析 Argument Construction
Situation Pressure within the earth’s iron core increases with depth. Because the melting temperature of iron increases with pressure, the inner core is solid and the outer core molten. Physicists can determine iron’s melting temperature at any pressure and the pressure it is under at any depth.
Reasoning What further premise, combined with the information provided, would support the conclusion that physicists can determine the temperature at the boundary between the outer and inner cores? Since physicists can determine iron’s melting temperature at any pressure and the pressure it is under at any depth, they must be able to determine its melting temperature at any depth. The temperature at the boundary between the inner and outer cores must exactly equal the melting temperature there, since that is the boundary between the molten and solid parts of the core. To determine the temperature at the boundary, therefore, it would suffice to know the depth of the boundary.
A Correct. If physicists know the depth of the boundary between the inner and outer cores, they can determine the temperature at the boundary.
B The fact that some heat flows from the core to the surface is too vague to help in determining exact temperatures anywhere.
C The difference in pressures between the outer core and the region above it is only vaguely described here and is not clearly relevant to the temperature at the boundary between the outer core and the inner core below it.
D An absence of information would not be helpful in determining the temperature at the boundary between the outer and inner cores.
E This information is not sufficiently specific to show that the temperature at the boundary between the outer and inner cores can be determined.
The correct answer is A.
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