Because mining and refining nickels is costly, researchers have develo

IMO B. It is the only strengthener here. And moreover B touches the commercial aspect as per Question stem.
ACE are weakener and D Out of scope.

[quote="kingb"]Because mining and refining nickels is costly, researchers have developed an alternative method for extracting nickels using Streptanthus polygaloides, a plant that absorbs and stores nickel from the soil as it grows. The researchers incinerated a crop of Streptanthus they grow in nickel-rich soil. By chemically extracting nickel form the ash, they produced 100 pounds of nickel per acre of land at a total cost per pound slightly above that of current mining.

Which of the following, if true, most strongly supports the conclusion that the use of Streptanthus to extract nickel will be commercially adopted?

A. The season in which the researchers grew Streptanthus was an unusually favorable one, with the right amount of precipitation to maximize the growth rate of Streptanthus. ......weakens
B. Because lowering the concentration of nickel in the soil can make land much better for agriculture in general, a plot in which Streptanthus has been grown and harvested can be sold for substantially more than it cost. .... ok good
C. More air pollution is generated for each pound of nickel produced by extracting it from Streptanthus than is generated using conventional mining and refining...... pollution is not the issue
D. The land on which the researchers planted Streptanthus was unusually free of the various weeds that can compete with Streptanthus for water, nutrients, and sunlight. weakens
E. It is extremely rare for soil to contain higher concentrations of nickel than the concentrations present in the researchers’ experimental plot. weakens

Because the new researched plant will help the farmer enrich soil with nickel. So, there are more people buy this kind of plant => more nickel will be collected effectively and even freely. Choice B is the correct choice.

A. The season in which the researchers grew Streptanthus was an unusually favorable one, with the right amount of precipitation to maximize the growth rate of Streptanthus. // no affect
B. Because lowering the concentration of nickel in the soil can make land much better for agriculture in general, a plot in which Streptanthus has been grown and harvested can be sold for substantially more than it cost // strenghtens by giving more reason as S growing is good
C. More air pollution is generated for each pound of nickel produced by extracting it from Streptanthus than is generated using conventional mining and refining // weakens
D. The land on which the researchers planted Streptanthus was unusually free of the various weeds that can compete with Streptanthus for water, nutrients, and sunlight. // weakens
E. It is extremely rare for soil to contain higher concentrations of nickel than the concentrations present in the researchers’ experimental plot. //no affect

Commercial use = Profit Maximization / Cost Reduction / Increase in Quantity at existing cost

Except option (B) none of the options are within the scope of Commercial usage of the plant ( Reasons highlighted in RED ), hence correct answer must be (B)

Because mining and refining nickels is costly, researchers have developed an alternative method for extracting nickels using Streptanthus polygaloides, a plant that absorbs and stores nickel from the soil as it grows. The researchers incinerated a crop of Streptanthus they grow in nickel-rich soil. By chemically extracting nickel form the ash, they produced 100 pounds of nickel per acre of land at a total cost per pound slightly above that of current mining.

Which of the following, if true, most strongly supports the conclusion that the use of Streptanthus to extract nickel will be commercially adopted?

The stimulus doesn't have a conclusion within itself. But it's conclusion is actually in the stem: Streptanthus will be adopted. So we are looking for an answer that say good things about Streptanthus.

(A) The season in which the researchers grew Streptanthus was an unusually favorable one, with the right amount of precipitation to maximize the growth rate of Streptanthus.

In the stimulus, researchers' goal is to decrease the price and decrease nickels. Even though we use Streptanthus, the cost is still higher. Now A is saying that, Streptanthus is grown in a good weather which is beneficial for the grow of Streptanthus. However, we don't have good weathers everyday. On days that have bad weather, Streptanthus will perform even worse. Not a strengthener.

(B) Because lowering the concentration of nickel in the soil can make land much better for agriculture in general, a plot in which Streptanthus has been grown and harvested can be sold for substantially more than it cost

Even though extracting nickels using Streptanthus is actually higher than the traditional mining techniques, we can also sell the lands that had used Streptanthus for higher profits. To be honest, I didn't like this answer choice even though it is correct. The reason I didn't like it is that, this choice sounds like we can make profits on the land simply because of small lower concentration of nickels but that can definitely be achieved by the traditional mining method, not just the Streptanthus method. But by reading other choice, we should be able to narrow down to B.

(C) More air pollution is generated for each pound of nickel produced by extracting it from Streptanthus than is generated using conventional mining and refining

First, it is out of scope. Decreasing air pollution is not our focus in this problem. Even it is, C is saying that Streptanthus will have more air pollution which weakens the argument.

(D) The land on which the researchers planted Streptanthus was unusually free of the various weeds that can compete with Streptanthus for water, nutrients, and sunlight.

Same as A, this answer choice is a weakener. The Streptanthus grown by researchers is under optimal conditions. But there are definitely many other land that don't have optimal conditions (bad water, little nutrients, little sunlight). Then in this case, Streptanthus will perform even worse.

(E) It is extremely rare for soil to contain higher concentrations of nickel than the concentrations present in the researchers’ experimental plot.

Same as A, this answer choice is a weakener. With such high concentration of nickels, and Streptanthus's costs is still hgh. Even we use Streptanthus on land that has lower concentration of nickels, Streptanthus will perform even worse. Argument is weakened.

Approach 1 to extract nickel : Mining and refining.
Approach 2 to extract nickel : SP, plant that absorbs and stores nickel

destroyed the crop containing nickel to ask-> chemically extracted nickel -> 100 ponds nickel per acre
Total cost per pound slightly above via mining.
From the question stem:
Conclusion : the use of SP to extract nickel will be commercially adopted

Approach : comparative approach:
we know out of 2 approaches one is to be adopted.

Advantage of the chosen one over the other.

Advantage=Benefit-Effort

we know that the effort (cost per acre in this case) is almost same, hence benefit of the SP has to offset the one of the mining.

Benefits via SP could be that:
1. the nickel extracted is in the purest form
2. the amount of nickel extracted is more.
3. people are willing to buy the nickel at higher price.
4. the nickel extracted doesn't add up to pollution and the people do care about it.
5. the nickel extraction may help with the condition of the land that would have been destroyed had the extraction been done using the mining.

(A) The season in which the researchers grew Streptanthus was an unusually favorable one, with the right amount of precipitation to maximize the growth rate of Streptanthus.
Irrelevant.

(B) Because lowering the concentration of nickel in the soil can make land much better for agriculture in general, a plot in which Streptanthus has been grown and harvested can be sold for substantially more than it cost
Perfect.Goes with benefit 5

(C) More air pollution is generated for each pound of nickel produced by extracting it from Streptanthus than is generated using conventional mining and refining
Weakener.

(D) The land on which the researchers planted Streptanthus was unusually free of the various weeds that can compete with Streptanthus for water, nutrients, and sunlight.
Irrelevant.

(E) It is extremely rare for soil to contain higher concentrations of nickel than the concentrations present in the researchers’ experimental plot.
Irrelevant.