题目选项分析

The discovery that Earth's inner core, rotating independently of and more quickly than Earth's outer layers, is responsible for advancing studies of the flow of heat from the inner through the outer planet and of how Earth's magnetic field forms and the periodic reversal of its direction.

The discovery that Earth's inner core rotates independently of and more quickly than Earth's outer layers is responsible for advancing studies of the flow of heat from the inner through the outer planet and of the formation and periodic reversal in direction of Earth's magnetic field.