Question 151·Hard·Cross-Text Connections
Text 1
In 2016, marine ecologist Lila Moreno monitored the recovery of the coral species Acropora digitifera after a major heatwave. Colonies dominated by the symbiotic alga Cladocopium D1a had far lower bleaching mortality than those dominated by Cladocopium C3. However, during the cooler year that followed, D1a-dominated colonies deposited less calcium carbonate than C3-dominated colonies. Moreno proposed that enhanced thermal tolerance might come with a cost to growth under benign conditions and recommended testing whether increasing food availability could reduce that cost.
Text 2
A 2021 laboratory study by Harker and Singh grew genetically similar coral fragments hosting either Cladocopium D1a or C3. Under alternating four-week periods of heat stress and normal temperatures, the D1a group survived heat stress at higher rates but calcified about 15% more slowly than the C3 group during normal-temperature periods. When the researchers provided supplemental zooplankton feedings three times per week, the calcification gap shrank to roughly 4%, and after eight weeks it was no longer statistically significant. The authors concluded that enhanced heterotrophic nutrition can offset growth deficits linked to heat-tolerant symbionts.
Based on the texts, if Moreno (Text 1) and Harker and Singh (Text 2) were aware of the findings of both studies, they would most likely agree with which statement?
For cross-text connection questions, briefly summarize each text’s main claim (especially any hypothesis in one text and any tested result in the other). Then choose the option that states the point of overlap: what Text 1 suggests or predicts and what Text 2’s findings support. Eliminate choices that introduce new recommendations, blame errors without textual support, or make stronger absolute claims than the texts justify.
Hints
Connect the research questions
In Text 1, notice what Moreno suggests should be tested about food availability and coral growth. What possible effect is she interested in?
Focus on the conclusion of Text 2
In Text 2, pay close attention to what happens after supplemental zooplankton feedings are added. How does the calcification gap between D1a and C3 change, and what conclusion do the authors draw?
Look for an option that both predicts and confirms the same idea
Which choice describes something that Moreno wants to investigate and Harker and Singh’s experiment supports? Eliminate choices that go beyond the texts (policy claims) or that contradict the feeding result in Text 2.
Step-by-step Explanation
Understand Moreno’s main claim (Text 1)
Moreno observes that colonies with the D1a symbiont survive heat better but grow more slowly (deposit less calcium carbonate) in the following cool year compared with C3 colonies. She proposes a tradeoff—thermal tolerance may come with a cost to growth under benign conditions—and she recommends testing whether increasing food availability could reduce that cost.
Understand Harker and Singh’s findings (Text 2)
Harker and Singh find a similar tradeoff in the lab: D1a fragments survive heat stress at higher rates but calcify about 15% more slowly than C3 fragments during normal-temperature periods. When supplemental zooplankton is provided, the calcification difference shrinks to about 4% and is no longer statistically significant after eight weeks, leading them to conclude that enhanced feeding can offset the growth deficit associated with heat-tolerant symbionts.
Identify the shared point of agreement
Text 1 raises a specific hypothesis/question about whether additional food could reduce the growth cost linked to heat-tolerant symbionts. Text 2 directly tests a version of that idea by adding supplemental feedings and observing how the calcification difference changes. So the best answer should connect increased food availability to a reduced growth penalty.
Match that shared idea to the answer choice
Only choice D states the shared idea that the texts point toward: Increasing corals' access to food can lessen the growth penalty associated with heat-tolerant symbionts.