Q40:
Two centuries ago, Tufe Peninsula became separated form the mainland, isolating on the newly formed Tufe Island a population of Turfil sunflowers. This population’s descendants grow to be, on average, 40 centimeters shorter than Turfil sunflowers found on the mainland. Tufe Island is significantly drier than Tufe Peninsula was. So the current average height of Tufe’s Turfil sunflowers is undoubtedly at least partially attributable to changes in Tufe’s environmental conditions.

Which of the following is an assumption on which the argument depends?

A. There are no types of vegetation on Tufe Island that are known to benefit from dry conditions.
B. There were about as many Turfil sunflowers on Tufe Peninsula two centuries ago as there are on Tufe Island today.
C. The mainland’s environment has not changed in ways that have resulted in Turfil sunflowers on the mainland growing to be 40 centimeters taller than they did two centuries ago.
D. The soil on Tufe Island, unlike that on the mainland, lacks important nutrients that help Turfil sunflowers survive and grow tall in a dry environment.
E. The 40-centimeter height difference between the Turfil sunflowers on Tufe Island and those on the mainland is the only difference between the two populations.
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cool

Two centuries ago, Tufe Peninsula became separated form the mainland, isolating on the newly formed Tufe Island a population of Turfil sunflowers. This population’s descendants grow to be, on average, 40 centimeters shorter than Turfil sunflowers found on the mainland. Tufe Island is significantly drier than Tufe Peninsula was. So the current average height of Tufe’s Turfil sunflowers is undoubtedly at least partially attributable to changes in Tufe’s environmental conditions.

Which of the following is an assumption on which the argument depends?

A. There are no types of vegetation on Tufe Island that are known to benefit from dry conditions. out of scope
B. There were about as many Turfil sunflowers on Tufe Peninsula two centuries ago as there are on Tufe Island today. irrelvent
C. The mainland’s environment has not changed in ways that have resulted in Turfil sunflowers on the mainland growing to be 40 centimeters taller than they did two centuries ago. weakening the argument
D. The soil on Tufe Island, unlike that on the mainland, lacks important nutrients that help Turfil sunflowers survive and grow tall in a dry environment. irrelevant
E. The 40-centimeter height difference between the Turfil sunflowers on Tufe Island and those on the mainland is the only difference between the two populations.strenthening the conclusion so correct answer for me

I'm going with C.

conclusion: changes are attributable to Turfe's environmental changes

evidence1: sunflower 40cm shorter than on the mainland
evidence": Tufe Island is dryer than mainland was 200 years ago

assumption: only the island's climate has changed

A. irrelevant
B. irrelevant
C. The mainland’s environment has not changed, best answer
D. argument is about climate and not nutrients
E. can not be assumed

im with C as well, when answering an assumption question, talking about things outside the scope of the question will be irrelevant. i.e. ( soil nutrients )

I'll go for C. It tells us temperature should be the only critical factor here, and the control case (sunflowers on mainland) is a fair comparison.