Question 30·200 Super-Hard SAT Reading Questions·Expression of Ideas
On hot desert flats, some plants open their microscopic pores mainly at night, limiting water loss during daytime heat. Botanist Amina Velasquez found that an alpine herb does the reverse: it closes its pores during cold nights and opens them after sunrise. The two timing patterns can therefore be described as opposites. _____ they are opposite only in relation to clock time; functionally, both shift gas exchange away from the period when local conditions make it most costly.
Which choice completes the text with the most logical transition?
For difficult transition questions, compare the precise logical functions of plausible options. In particular, distinguish a restatement, which expresses the same claim again, from a refinement, which narrows, qualifies, or makes the earlier claim more exact.
Hints
Track the scope of the claim
Consider how the word “only” affects the earlier description of the timing patterns as opposites.
Distinguish refinement from restatement
Determine whether the final sentence repeats the preceding claim unchanged or limits the conditions under which that claim is accurate.
Step-by-step Explanation
Identify the initial characterization
The text calls the two timing patterns opposites because one plant opens its pores mainly at night while the other opens them after sunrise.
Examine how the final sentence changes that claim
The final sentence limits the sense in which the patterns are opposite: they differ with respect to clock time, but both avoid the locally costliest period for gas exchange.
Choose the relationship
Because the final sentence makes the preceding characterization narrower and more exact rather than merely repeating it, a transition that signals refinement is needed.