Q20

[zainrizvi]

I don't see how (B) strengthens the argument

Doesn't the passage suggest that examining magenetite grains is a valid method?

I thought (C) would strengthen the argument as it would show that the basalt measured in continental volcanic rocks is similar to the basalt found in the ocean.

[noah]

Good question.

As I'm sure you know, the theory is that the ocean floor is slowly spreading out from these ridges. The support is that if we assume the spreading is a few cm. per year, the magnetic reversals (recorded in the rock), which have been dated by looking at volcanic rocks, occur in the right places in the rock by the ridges.

(B) strengthens the argument because it verifies the age of the reversals. In the passage, the dates were "assigned" by scientists - which is far less credible than "verified."

(A) is out of scope - who cares if other rock is magnetic? Frankly, I'd assume there are!

(C) places basalt on land as well as in the ocean. However, that doesn't support the theory in any way. Even if we knew that the basalt found on land was the rock that was used to date the reversals, we have no reason to think that the dating process is somehow better since the rock is in both places.

(D) is irrelevant. The height of the ridge is not germane to the theory.

(E) is nifty but irrelevant. We are only discussing basalt - who cares if there is not (or is) other volcanic rock at play?

That clear it up?

[AnnaC659]

Good question.

As I'm sure you know, the theory is that the ocean floor is slowly spreading out from these ridges. The support is that if we assume the spreading is a few cm. per year, the magnetic reversals (recorded in the rock), which have been dated by looking at volcanic rocks, occur in the right places in the rock by the ridges.

(B) strengthens the argument because it verifies the age of the reversals. In the passage, the dates were "assigned" by scientists - which is far less credible than "verified."

(A) is out of scope - who cares if other rock is magnetic? Frankly, I'd assume there are!

(C) places basalt on land as well as in the ocean. However, that doesn't support the theory in any way. Even if we knew that the basalt found on land was the rock that was used to date the reversals, we have no reason to think that the dating process is somehow better since the rock is in both places.

(D) is irrelevant. The height of the ridge is not germane to the theory.

(E) is nifty but irrelevant. We are only discussing basalt - who cares if there is not (or is) other volcanic rock at play?

That clear it up?

Thank you Noah.
After reading the thread, I finally understand how B strengthens the theory.
But during timed sessions I almost always find it extremely difficult to go back to the passage to find the relevant line for this type of questions... so end up choosing based on guts between what i have left after POE. I try to do passage map and all but can't seem to remember this kind of details. Any advice?

Thank you in advance.

[ohthatpatrick]

Sorry for the late (and unsatisfying) response.

Virtually no one is absorbing enough of the passage on the first read to answer this question without looking back.

So there's no cheat code or workaround for that. For some of us, based on our reading and processing speed, there's just not enough time in a 35 minute section to do our best on all 28 RC questions.

Thus, part of the art form of improving at RC is accepting that and trying to gameplan accordingly:

- should we try to trim down our upfront reading time?
If it's currently above 3 mins, it's gotta come down to at most 3. If it's currently around 3, maybe we try to bring it down to 2. A lot of people have pretty unimpressive retention after the first read. If that's the case, then forcing yourself to finish the first read sooner can be a good value. If we're not really retaining much of what we're reading, then let's get a quick big picture and free up some time so that we can read little snippets as we're doing the questions.

- should we skip some of the hardest questions?
If we skipped the worst question in every passage, that might buy us enough time to get strong answers at everything else, because we would permit ourselves the time to look stuff up in the passage. This question might actually BE one of the ones you skip, because Strengthen/Weaken/Analogy/New Last Sentence questions are often time consuming and lower accuracy (since they involve new ideas that weren't already in the passage).

The keywords on this question stem are "the ocean floor spreading theory", and the Support Window of text seems to start at line 33 and go all the way through line 55.

Since this question demands that we re-read a healthy chunk of text, we can recognize early on that this could be a time trap.

Hope this helps.

[abrenza123]

Just to clarify - With this line of evidence for ocean spreading theory, does the passage imply that geologists dating the ocean floor rocks by the assumed rate of ocean floor spreading per year to help establish the correlation between the striping pattern and the assigned age of magnetic reversals?