lo and Europa, the inner two of Jupiter's four largest moons, are about the size of Earth’s moon and are composed mostly or entirely of rock and metal. Ganymede and Callisto are larger and roughly half ice. Thus, these four moons are somewhat analogous to the planets of the solar system, in which the rock- and metal-rich inner planets are distinct from the much larger gas- and ice-rich outer planets. Jupiter's moons are, however, more "systematic" :many of their properties vary continuously with distance from Jupiter. For example, lo is ice-free, Europa has a surface shell of ice, and while Ganymede and Callisto are both ice-rich, outermost Callisto has more.This compositional gradient has geological parallels, lo is extremely geologically active, Europa seems to be active on a more modest scale, and Ganymede has undergone bouts of activity in its geological past. Only Callisto reveals no geological activity. In similar fashion, Callisto's surface is very heavily cratered from the impact of comets and asteroids; Ganymede, like Earth’s moon, is heavily cratered in parts; Europa is very lightly cratered; and no craters have been detected on lo, even though Jupiter's gravity attracts comets and asteroids passing near it, substantially increasing the bombardment rate of the inner moons compared to that of the outer ones. But because of lo's high degree of geological activity, its surface undergoes more-or-less continuous volcanic resurfacing.

Which of the following best describes the purpose of the second paragraph of the passage?

 A to provide further evidence of the systematic variation in the characteristics of Jupiter's four largest moons

 B to present a comprehensive theory to explain the systematic variation in the characteristics of Jupiter’s four largest moons

 C to explain the significance of the systematic variation in the characteristics of Jupiter's four largest moons

 D to introduce facts that contradict conventional assumptions about Jupiter’s four largest moons

 E to contrast the characteristics of Jupiter’s four largest moons with the characteristics of the planets of the solar system

【申友解析】

第二段首句的This compositional gradient has geological parallels说明该段是承接了第一段的“构成物上的梯度变化”。

A正确。其中的further evidence表示第二段承接第一段的内容

B错误。第二段是承接上一段的内容继续论述，而并不是解释第一段的某个现象。此处的explain不对

C错误。并没有提到significance

D错误。没有提到contradict conventional assumptions

E错误。与太阳系的行星的特点无关，这是第一段讨论的内容

☞"预约名师一对一题目解析课程"