Researchers have studied the cost-effectiveness of growing halophytes—

Do we have to consider info related to desert regions?

This is a strenghtening question, so we need to try to find a gap in the argument so that one of the options can eliminate it.

Background: Researchers -> halophytes -> cost-effective
1ºCounterPremise: halophytes -> more water (not good)
1ºPremise -> halophytes -> seawater -> cheaper
2ºCounterPremise: seawater ->less yields (not good)

So we need to strenghten that halophytes are cost-effective. To do that we need an option that either eliminates the 2 counterpremises, which are not good or that finds more importante premises in favour of halophytes. One las thought before starting. Please realize that no measures are given. More water, less yields, cheaper, etc. So an option that helps us know by how much is all of this to finally conclude that indeed it is actually cost effective would be what we are looking for. Let's start

(A) A given volume of halophytes is significantly different in nutritional value for animal forage from the same volume of conventional forage crops.

Different in nutrional value, but better or worse nutrional value? It doesn't secify so this cannot be the answer. Incorrect

(B) Some halophytes not only tolerate seawater but require salt in order to thrive.

Seawater has salt so it doesn't make sense. But if it didn't require it. This is a weakness because it requires something that wasn't mention in the argument, therefore, it is more costly and therefore it is less cost/efficient. Incorrect

(C) Large research expenditures are needed to develop the strains of halophytes best suited for agricultural purposes.

research expenditure menas less cost-effective. This is a weakness. Incorrect

(D) Costs other than the costs of irrigation are different for halophytes grown by means of seawater irrigation than for conventional crops.

Again it says different, but we don't know if more or less so we can't evaluate it. Incorrect


(E) Pumping water for irrigation is proportionally one of the largest costs involved in growing, harvesting, and distributing any forage crop for animals.

Aha! this is the answer. It says tha pumping costs are the most important ones in irrigation. And the argument mentioned that pumping costs for seawater are cheaper. Therefore, this shows that halophytes are cost-effective. Correct

How's E a strengthener ? It just says that it is one of the largest costs. But there maybe other costs which are higher for seawater agriculture. Please guide.

azhrhasan , we are never told that any costs for seawater are higher than those for conventional freshwater agriculture.
Your argument is very sensible. It is realistic. But it is not supported by a single word in the prompt.

In CR and LR, stay only with the facts that are given to you.
I would avoid focusing on what you do not know and what is not mentioned in the prompt.

Try not to "import" facts that are not in the premises and conclusion.
Doing so plays right into the hands of LSAC.

Having practiced thousands of these questions and taken the LSAT with 50+ of these bad boys, I promise that this approach works: stay with the text you are given.

Sure, there may be other costs that are higher in seawater agriculture than in conventional agriculture.
We don't care about them, at all, because we know absolutely nothing about them.
We cannot be asked to evaluate something about which we know nothing.
Pretend these other theoretically high seawater agriculture costs don't exist.
They are not mentioned in the prompt and as such the conclusion does not depend on them.

We are here to find something that strengthens the (very specific) conclusion.

(E) Pumping water for irrigation is proportionally one of the largest costs involved in growing, harvesting, and distributing any forage crop for animals.

This fact supports the claim of cost-effectiveness in the conclusion.

At every stage of agriculture, pumping fresh water is proportionally one of the largest costs.
If I do this sea level desert seawater agriculture, using "much cheaper" pumped seawater, I save a lot of money at every stage of the process.
If we know (E), then we have strengthened the conclusion.
One of the proportionally largest costs just got a lot cheaper. Sounds cost-effective to me.

I hope that helps.

Strengthen question

We are given two methods to grow forage for animals: one involves seawater and the other one involves normal water.

All that we know is that pumping seawater is more cost effective than pumping normal water. From this evidence the conclusion is drawn: seawater agriculture is more cost effective than normal agriculture even tough the yields are smaller.

The argument relies on the fundamental assumption that there are no other relevant costs involved in seawater agriculture that are not involved in normal agriculture.

While all the other statements do not impact the argument option E strengthen our assumption by stating that pumping water for irrigation is the largest cost involved.

To increase the strength of the conclusion, we need to find a choice that shows that seawater agriculture of halophytes, despite its smaller yield, is cheaper than freshwater agriculture.

(A) WRONG: different doesn't imply better or worse, plus we're concerned with the cost of seawater agriculture vs. freshwater agriculture of halophytes, not conventional crops
(B) WRONG: tempting choice but some (could be just one) halophytes requiring saltwater doesn't say anything about why seawater agriculture could be cheaper than freshwater agriculture
(C) WRONG: if anything, this weakens the use case of halophytes as a whole
(D) WRONG: different doesn't imply cheap or expensive, plus we're concerned with seawater agriculture vs. freshwater agriculture of halophytes
(E) CORRECT: pumping freshwater compared to all other costs combined is the largest, therefore cutting out this cost would mean seawater halophytes would be much cheaper even with the low yield

Researchers have studied the cost-effectiveness of growing halophytes—salt-tolerant plant species—for animal forage. Halophytes require more water than conventional crops, but can be irrigated with seawater, and pumping seawater into farms near sea level is much cheaper than pumping freshwater from deep wells. Thus, seawater agriculture near sea level should be cost-effective in desert regions although its yields are smaller than traditional, freshwater agriculture.

Which one of the following, if true, most strengthens the argument above?
(A) A given volume of halophytes is significantly different in nutritional value for animal forage from the same volume of conventional forage crops. - WRONG. Does nutritional value results in cost-effectiveness? Not sure.
(B) Some halophytes not only tolerate seawater but require salt in order to thrive. - WRONG. Nothing new as its already in the passage. Also, does it impacts cost part. Not sure.
(C) Large research expenditures are needed to develop the strains of halophytes best suited for agricultural purposes. - WRONG. Somewhat weakener if at all.
(D) Costs other than the costs of irrigation are different for halophytes grown by means of seawater irrigation than for conventional crops. - WRONG. If different then how different and what impact it has on the cost-effectiveness of the seawater irrigation.
(E) Pumping water for irrigation is proportionally one of the largest costs involved in growing, harvesting, and distributing any forage crop for animals. - CORRECT. Spot on as it touches the cost-effectiveness aspect of the passage.

Answer E.