PT6.S3.Q17 - Carbon dating skeptics

beepbooptroupe

I'm having a lot of trouble understanding the stimulus's support for [A] being the correct weaken answer.

I eliminated it because the skeptics never said that it was just the bottom layer that was contaminated; they just say "the samples were contaminated" so I thought that they were referring to the entire collection, which would include the upper layer. The skeptics never differentiated between the uppermost and lower samples for their hypothesis, so AC [A] doesn't seem to weaken their hypothesis at all.

How can I infer that they're excluding the uppermost samples in their hypothesis? Is it because the stimulus says that the uppermost samples are dated to the present and therefore couldn't have been contaminated by the old carbon?

tattoinesuns

The stimulus states that skeptics viewed "that" date as too early. With referential phrasing, we can determine "that" as the oldest, deepest sample dated to 19,560 years before the present (in the previous sentence). The skeptics never say that the date of the uppermost sample is too early or inconsistent. If A were true, then the skeptics would have to also have an issue with the uppermost (or present) layer, which they do not. Hope that helped!