PT 15 S1 Q7

Until the 1980s, most scientists believed that non-catastrophic geological ... ...

Which one of the following, if true, would cast the most doubt on the theory described in the last paragraph of the passage?
(A) Fragments of meteorites that have struck the Earth are examined and found to have only minuscule amounts of iridium hexafluoride trapped inside of them.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: Science & Technology Mix 2