No8-1 AS Q19:TYPICAL?

HardyNiborUID：3461489

The best evidence for the layered mantle thesis is the well-established fact that volcanic rocks found on oceanic islands, islands believed to result from mantle plumes arising from the lower mantle, are composed of material fundamentally different from that of the midocean ridge system, whose source, most geologists contend, is the upper mantle.

We believe, perhaps unimaginatively, that this debate can be resolved through further study, and that the underexplored midocean ridge system is the key.

19. It can be inferred from the passage that the supporters of the “layered-mantle” theory believe which of the following?

II. The materials of which volcanic rocks on oceanic islands and midocean ridges are composed are typical of the layers from which they are thought to originate.

到底选不选？

crazyrobinUID：2368627

不选吧
Layered-mantle supporters只是说rock的material跟mid ocean 不一样。 后者的组成部分还是most geologists的观点。
他们并没有认为这个是不是typical.
Typical这里可以理解为 representative