Question 121·Easy·Inferences
Marine biologist Dr. Li monitored a severe coral bleaching event on a Pacific reef. She noted that while many corals died, colonies of Porites cylindrica remained healthy. Laboratory analysis showed that these surviving corals contained unusually high concentrations of a strain of algae known to tolerate warm water.
From the information provided, it can best be inferred that Porites cylindrica corals that host large amounts of heat-tolerant algae most likely ______
Which choice most logically completes the text?
For SAT inference questions that ask what can "best be inferred" or "most logically completes the text," base your answer strictly on what the passage actually says or clearly implies, not on outside knowledge or guesses. First, restate the key facts in your own words, especially cause-and-effect links (for example, what trait is associated with survival). Then, test each answer: if it introduces a new idea (like growth rate, sunlight needs, or mutations) that the passage never mentions or hints at, cross it out. Choose the option that rephrases or directly extends the passage’s information without adding unsupported details.
Hints
Locate the cause of survival
Reread the sentences about which corals survived the bleaching event and what was special about them. What detail does the passage give that explains why Porites cylindrica colonies stayed healthy?
Pay attention to the phrase about the algae
Focus on the description of the algae: it is a strain "known to tolerate warm water." Think about what kind of event is being described and why that quality of the algae would matter.
Eliminate answers that add new ideas
Ask yourself for each choice: Is this idea (about sunlight, growth, or mutations) actually mentioned or clearly suggested by the passage, or is it introducing something new that the passage never talks about?
Step-by-step Explanation
Identify the key events in the scenario
First, summarize what happens:
- There is a severe coral bleaching event on a Pacific reef.
- Many corals died, but colonies of Porites cylindrica remained healthy.
So Porites cylindrica corals survived a harmful event that killed many others.
Focus on the scientific explanation given
Next, look at the explanation:
- Laboratory analysis showed the surviving Porites cylindrica corals contained unusually high concentrations of a strain of algae.
- This strain of algae is known to tolerate warm water.
So, there is a connection: the corals that stayed healthy have lots of algae that can handle warm water.
Connect cause and effect
Ask: What can we logically infer about Porites cylindrica that host large amounts of this heat-tolerant algae?
- The bleaching event is associated with warm water.
- Corals with lots of heat-tolerant algae were the ones that remained healthy.
The most direct, text-based inference is about how these corals deal with elevated water temperatures, not about other traits like growth rate or light needs.
Test each answer choice against the passage
Now compare each option to the information:
- A) are better able to withstand elevated water temperatures. This directly fits the situation: during a warm-water bleaching event, the corals with heat-tolerant algae stayed healthy, so they are most likely better at enduring higher temperatures.
- B) require less sunlight for photosynthesis. The passage never mentions sunlight levels.
- C) grow at a faster rate than other coral species. No growth rates are discussed.
- D) have recently evolved new genetic mutations. The passage says nothing about mutations or how recent any changes are.
Only choice A) are better able to withstand elevated water temperatures. is clearly supported by the given information.