Question 114·200 Super-Hard SAT Reading Questions·Expression of Ideas
Researchers investigating drought tolerance in wild sunflowers found that plants carrying a particular DNA variant near a water-transport gene survived dry conditions at higher rates. Because nearby variants are often inherited together, however, this field association could not identify the particular variant responsible. The researchers later altered only the candidate variant in otherwise genetically identical plants and observed increased drought survival. This experiment therefore strengthens the case that the candidate variant itself contributes to drought tolerance. ______ it shows that changing the variant can affect survival when genetic background is held constant; it does not establish how strongly the variant affects survival amid the environmental variation of natural populations.
Which choice completes the text with the most logical transition?
For a challenging transition question, determine the function of the entire sentence containing the blank rather than matching a transition to one conspicuous clause. When a sentence contains both a supporting statement and a limitation, ask whether its overall role is to oppose, refine, exemplify, or derive a result from the preceding idea.
Hints
Compare the levels of specificity
Determine whether the sentence after the blank opposes the preceding claim, results from it, compares it with another finding, or states its scope more exactly.
Consider both clauses
Do not select a transition based only on the limitation after the semicolon. The transition must describe the role of the entire sentence.
Step-by-step Explanation
Identify the preceding claim
The preceding sentence makes the broad claim that the editing experiment strengthens the case for the candidate variant's contribution to drought tolerance.
Examine the entire final sentence
The final sentence defines the limits of that claim: the experiment shows that changing the variant can affect survival under controlled genetic conditions, but it does not determine the strength of the effect in natural populations.
Choose the relationship
Because the final sentence states the preceding claim in a more exact and carefully limited way, “More precisely” is the most logical transition.