Question 150·Hard·Inferences
For decades, marine biologists have studied coral bleaching events to determine their causes. Early research focused primarily on rising sea surface temperatures, but more recent studies have revealed that high levels of ocean acidity can intensify bleaching episodes even when temperatures are relatively stable. Because both stressors often occur simultaneously, separating their individual impacts has proved challenging. Nevertheless, by analyzing reefs located at cold-water upwellings, researchers have shown that coral colonies can survive short-lived heat spikes if the surrounding water remains moderately alkaline. This finding suggests that ______
Which choice most logically completes the text?
For inference-style sentence completions, identify what the reference phrase (here, “This finding”) points to, paraphrase that evidence in your own words, and choose the option that makes a modest, logically supported takeaway. Eliminate options that introduce absolute language (e.g., “only”), add frequency claims (“rarely”), or shift to a different conclusion than the evidence supports.
Hints
Focus on the sentence before the blank
What specific condition is given for corals surviving short-lived heat spikes?
Translate “moderately alkaline”
Moderately alkaline means the water is not very acidic. What does that imply about acidification and resilience during warming?
Avoid choices that add new claims
Pick the option that stays close to the passage’s evidence (heat spikes + alkalinity) rather than introducing broad or unrelated conclusions.
Step-by-step Explanation
Identify what “this finding” refers to
The blank follows “This finding suggests that,” so look to the immediately preceding sentence for the finding:
Researchers have shown that coral colonies can survive short-lived heat spikes if the surrounding water remains moderately alkaline.
So the key idea is: lower acidity (more alkaline water) can help corals survive brief warming.
Turn the finding into an implication
If corals withstand temporary heat spikes when water is moderately alkaline, then controlling acidity should improve resilience to some temperature stress.
So the best completion should connect curbing acidification with withstanding temporary temperature increases, using cautious language (e.g., “may help”).
Select the choice that matches the implication
Only one option directly reflects the passage’s implication that less acidic conditions can help corals endure short-term warming:
efforts to curb ocean acidification may help reefs withstand temporary increases in temperature.