Critical Reasoning

In Colorado subalpine meadows, nonnative dandelions co-occur with a native flower, the larkspur. Bumblebees visit both species, creating the potential for interactions between the two species with respect to pollination. In a recent study, researchers selected 16 plots containing both species; all dandelions were removed �om eight plots; the remaining eight control plots were left undisturbed. The control plots yielded significantly more larkspur seeds than the dandelion-free plots, leading the researchers to conclude that the presence of dandelions facilitates pollination (and hence seed production) in the native species by attracting more pollinators to the mixed plots.

Which of the following, if true, most seriously undermines the researchers' reasoning?

A. Bumblebees preferentially visit dandelions over larkspurs in mixed plots.

B. In mixed plots, pollinators can transfer pollen from one species to another to augment seed production.

C. If left unchecked, nonnative species like dandelions quickly crowd out native species.

D. Seed germination is a more reliable measure of a species' �tness than seed production.

E. Soil disturbances can result in fewer blooms, and hence lower seed production.

I was down to Option C and Option E in this question.
I think that this is a causal argument =

the presence of dandelions facilitates pollination (and hence seed production) in the native species by attracting more pollinators to the mixed plots.

We need to find an option that breaks this causality. Is my Line of reasoning correct?

richachampion wrote:I was down to Option C and Option E in this question.
I think that this is a causal argument =

the presence of dandelions facilitates pollination (and hence seed production) in the native species by attracting more pollinators to the mixed plots.

We need to find an option that breaks this causality. Is my Line of reasoning correct?

Check my two posts here:
https://www.beatthegmat.com/subalpine-me ... 85831.html

GMATGuruNY wrote:
Check my two posts here:
https://www.beatthegmat.com/subalpine-me ... 85831.html

Thanks. I read both of your posts.
I have one more reason to discard the Option C. Please let me Know sir that if my reasoning is correct.
Let me first introduce a mathematical analogy.

Suppose there is a question that asks-
Is 4X > 3Y

No If we add 2 to both the side

It will become
Is 4X + 2 > 3Y + 2

The question is still the same because the new information that is addition of the quantity "+2" on both the side doesn't make any changes in the Inequality, and still we are on the same page since we do not know the values of X and Y we can't solve the question whether 4X > 3Y

Same is happening in our case in the question.
C. If left unchecked, non-native species like dandelions quickly crowd out native species.

"dandelions " is present in both the plots so it is just like that "+2" analogy it("dandelions") will have an equal effect on both the plots and as was the case in the mathematical Inequality where the addition of "+2" didn't change the question similarly here the Option C actually doesn't provide anything.

This option is actually a distractor. Right?

richachampion wrote:

GMATGuruNY wrote:
Check my two posts here:
https://www.beatthegmat.com/subalpine-me ... 85831.html

Thanks. I read both of your posts.
I have one more reason to discard the Option C. Please let me Know sir that if my reasoning is correct.
Let me first introduce a mathematical analogy.

Suppose there is a question that asks-
Is 4X > 3Y

No If we add 2 to both the side

It will become
Is 4X + 2 > 3Y + 2

The question is still the same because the new information that is addition of the quantity "+2" on both the side doesn't make any changes in the Inequality, and still we are on the same page since we do not know the values of X and Y we can't solve the question whether 4X > 3Y

Same is happening in our case in the question.
C. If left unchecked, non-native species like dandelions quickly crowd out native species.

"dandelions " is present in both the plots so it is just like that "+2" analogy it("dandelions") will have an equal effect on both the plots and as was the case in the mathematical Inequality where the addition of "+2" didn't change the question similarly here the Option C actually doesn't provide anything.

This option is actually a distractor. Right?

This line of reasoning does not apply to the CR above.
To leave X unchecked means not to monitor or control X.
C: If left unchecked, non-native species like dandelions quickly crowd out native species.
Since the dandelion plots in the CR above were monitored -- and thus were checked -- this option is irrelevant.