OG 17 CR 題號 545

545.

Astronomer: Most stars are born in groups of thousands, each star in a group

forming from the same parent cloud of gas. Each cloud has a unique, homogeneous

chemical composition. Therefore, whenever two stars have the same chemical

composition as each other, they must have originated from the same cloud of

gas.

Which

of the following, if true, would most strengthen the astronomer』s argument?

A In some groups of stars, not every star

originated from the same parent cloud of gas.

B Clouds of gas of similar or identical

chemical composition may be remote from each other.

C Whenever a star forms, it inherits the chemical

composition of its parent cloud of gas.

D Many stars in vastly different parts of the

universe are quite similar in their chemical compositions.

E Astronomers can at least sometimes precisely

determine whether a star has the same chemical composition as its parent cloud

of gas.

考點：三者搭橋增強

天文學家： 大部分星以幾千為一組產生，一組裡每顆星從同樣的父氣雲產生。每團雲有獨特的，一致的化學成分。因此，無論何時兩顆星有相同化學成分，它們起源於同一氣雲。

邏輯鏈條：三者搭橋

已知star－cloud gas chemical composition －cloud gas

增強角度：star－chemical composition

A

same parent cloud 無關

B.remote

跟距離無關

C.star-chemical

搭橋成功

D.跟相似性無關

E.determine

主觀 危險選項

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