Q19

[MayaM405]

Hi! I had a hard time with this question.

I narrowed down the answer choices to D and E.

D I see is supported by the first line "Dowsing is the practice of detecting resources or objects beneath the ground" (Lines 1-2)

But I considered E to be supported by the "minute changes in Earth's electromagnetic field associated with variations in subsurface conditions" (Lines 41-42)

While I see D is more directly supported upon review, I had selected E because I did not feel like I could eliminate it. Are these changes not "surface clues?" How/why should we eliminate this answer?

Thanks!

[ohthatpatrick]

There's no way to guess where this question stem is going, so we dive right in (or skip it, since they can be time consuming).

(A) meh, so extreme. I doubt they said when dowsing was FIRST employed. I'll check it later if I need to, but I'm assuming that's a trap. Softly eliminate.

(B) Hmm. How does dowsing work again? They are detecting variations in subsurface conditions, such as the electromagnetic field. So, would a soaking rain affect that? Probably not, since we're talking about finding pools of groundwater ... sensing holes in the bedrock .... I don't think that has anything to do with wet dirt. But maybe the rain is changing the subsurface conditions. Keep it.

(C) meh, so specific. What there ever a PERCENTAGE or FRACTION quoted? I don't think so, so we don't know what PROPORTION use forked sticks. Eliminate.

(D) Can't remember whether this was said, so I'll go looking back towards the early part of the passage, because I think the later parts were mainly about analyzing the accuracy of dowsing. The early part would have been an introduction to dowsing that may have mentioned this. [Looking back at first couple sentences ...] YUP! Looks good. The first sentence that dowsing is used to find "resources or objects", so it's more than just water. Pick it.

(E) This would be P2 probably. [scanning it ... lines 21-22 talk about the surface conditions but don't mention any specifics] Also, wasn't the author ultimately saying that dowsing seems to work by detecting SUBSURFACE conditions? So there shouldn't be an answer to this question, since dowsers AREN'T using surface conditions.

I would be down to (B) and (D), but whereas I'd have to work with my own thoughts a lot to talk myself into (B), I have line 1-2 to convince me of (D).

Hope this helps.

[JinZ551]

I think the correct answer is also supported by the last sentence: "...and on request even located a dry fracture zone, ...", which means it can be used to locate something (a dry fracture zone) other than water.