#25 - In ancient Mesopotamia, prior to 2900 B.C., wheat was cultivated in considerable quantities

[Dave Killoran]

Complete Question Explanation

Strengthen, Cause and Effect. The correct answer choice is (B).

This is a good example of how the last question in a section isn't automatically a difficult question.

The stimulus opens by providing the facts that prior to 2900 BC wheat was cultivated in large quantities but after 2900BC it began to decline as the production of barley rose. It might be easy to jump the conclusion that the rise in barley was the cause of the wheat decline, but you shouldn't do that and neither does the stimulus. Instead the author cites historians who believe there was a different set of related causes for the decline in wheat production: excessive irrigation, lack of drainage, and ultimately the accumulation of salt in soil. No further evidence or support is provided for their view, and thus it is no surprise when the question stem asks you to focus on this statement, and find an answer that supports it.


Answer choice (A): This answer certainly would provide some explanation for why barley production increased, but does it support the historians' explanation? No, there's no mention of the overirrigation/drainage/salt cycle they cited, and we can't assume this answer supports that explanation.

Answer choice (B): This is the correct answer choice. This answer helps support the idea that the cause cited would allow for the wheat decline and the barley increase. On a more abstract level, salt was the key to the historians' explanation, and you'd have to expect the correct answer would in some way support or address the salt issue.

Answer choice (C): This answer is in harmony with the idea that wheat was more widely produced prior to 2900 BC, but it does not address why that ratio suddenly flipped around 2900 BC. In other words, it doesn't address or support the historians' view.

Answer choice (D): This answer provides an explanation for why the wheat production dropped, but it does not explain why barley suddenly replaced wheat.

Answer choice (E): This addresses an expected effect of barley production increasing, but it does not address whether the historians' explanation of salt concentration is viable.

[rlouis1993]

Did you all ever get around to an explanation?

[Dave Killoran]

Did you all ever get around to an explanation?

Please see above--thanks!

[sxzhao]

I understand how B appears as the winner as compared to other choices, but I was still hesitant, because

the historian's contention is: wheat decline was due to excessive irrigation, lack of drainage, salty soil etc. - i.e., the historian's contention concerns the REASON for wheat's decline. In my head, I was making the prediction that to strengthen the argument, one will have to show that people then didn't give up wheat for some other reasons, like voluntarily switched to barley becasye wheat as a crop wasn't as productive as barley

choice (b), by showing barley could thrive in salty soil, provides for evidence that "yes indeed the soil was salty", but to me it simply repeats part of the contention already mentioned without strengthening the causal relations

Is there any material I could refer to to educate myself on WHAT to strengthen when asked to strengthen an argument?

[Luke Haqq]

Hi sxzhao!

You ask,

Is there any material I could refer to to educate myself on WHAT to strengthen when asked to strengthen an argument?

In general, it's the conclusion of the argument that one must strengthen on strengthen questions. It's thus imperative to make sure that you've correctly identified the conclusion in a given stimulus. Here, it's the final sentence: "Some historians who study ancient Mesopotamia contend that the decline in wheat production was due to excessive irrigation, lack of drainage, and the consequent accumulation of salt residues in the soil."

To your question about materials you could refer to, if you have PowerScore's course books, I'd recommend taking a look at lesson 4. That lesson covers strengthen questions. It also goes in depth into causal reasoning in strengthen questions--for example, one can strengthen causal reasoning by showing when the cause occurs, the effect is always present, or one can show that it's not the case that causal relationship is in fact reversed, etc.

[JotaDay]

Hi There - I still don't completely understand why something as unrelated as Barley increasing would help to prove that it was the increased levels of salt that drove down the wheat production. This answer choice, to me, did not strengthen the connection between those two events or prove causality.

[Jeff Wren]

Hi JotaDay,

First, it's important to realize that this is a Strengthen question, so you aren't being asked to prove anything. In fact, it is nearly impossible to prove for certain that one thing caused something else. (You'd have to rule out every other possibility). This is why causal arguments usually appear in Weaken and Strengthen (and sometimes Flaw) questions on the LSAT.

The facts in the argument are that, prior to 2900 B.C, wheat was widely cultivated. After 2900 B.C., production of wheat declined while barley sharply increased. There could be many explanations for why this occurred. Perhaps barley was cheaper, or more nutritious, or better tasting, or easier to farm, etc., and so the Mesopotamians decided to replace the wheat with barley for one of these reasons.

The historians, though, offer a different explanation. They argue that the decline in wheat was caused by excessive irrigation and lack of drainage, which then increased the salt in the soil.

Often it can be helpful to first think about how to weaken an argument before moving on to how strengthen it (since strengthening is simply the opposite of weakening).

Since we know that barley grew after 2900 B.C., if barley was also susceptible to salt in the soil (in the same way as wheat), then that would weaken the historians argument. In other words, if the decline in wheat was caused by salt in the soil, then how was barely able to grow? Wouldn't the salt have caused the same problem for barley?

However, since we're actually trying to strengthen the argument rather than weaken it, we'd like to do the exact opposite and show that barley could in fact grow in the conditions that the historians stated. If barley actually has a greater resistance to salt in the soil than wheat (as Answer B states), this supports the historians argument by providing a plausible explanation for what happened consistent with the historians argument. In other words, what seems reasonable to have happened is that the salt in the soil harmed the wheat crop, and so the Mesopotamians replaced wheat with barley because barley isn't harmed by the salt in the soil as much. Does this 100% prove that this is what happened? No. Fortunately, we don't need to 100% prove the causal argument, merely offer some support for it, which Answer B does.