Question 127·Easy·Inferences
Marine biologists studying coral reefs off the coast of Island X noted that a brightly colored fish species long common on the reefs was missing from surveys taken after a sharp rise in water temperature in 2015. When the scientists explored cooler, deeper waters near the island, they discovered large populations of the same fish. This evidence suggests that ______
Which choice most logically completes the text?
For inference completion questions that ask what the evidence "suggests," treat the blank as if it begins with "Therefore" or "This shows that." First, identify the key facts and any clear change over time or contrast (here, before vs. after 2015 and shallow vs. deep waters). Then, ask what simple explanation connects those facts directly. Use process of elimination to remove choices that introduce new topics or causes not mentioned (like fishing or pollution) or that shift focus away from the main subject. The best answer will restate or logically extend what is already in the passage without adding unsupported ideas.
Hints
Focus on the key event
Reread the sentence about what happened in 2015. What major environmental change is mentioned, and what happened to the fish on the shallow reefs right after that?
Compare the two locations
Think about the difference between the shallow reefs and the deeper waters where the fish were later found. What important quality of the water is different in those two places?
Look for an option that uses both clues
Which answer choice explains both why the fish disappeared from the shallow reefs after the event in 2015 and why they were later found in large numbers in the deeper waters nearby?
Step-by-step Explanation
Identify what changed in the situation
First, note the timeline and change described:
- Before 2015: The brightly colored fish species was long common on the shallow coral reefs.
- After a sharp rise in water temperature in 2015: The fish was missing from surveys on those reefs. This tells you something changed after the water warmed.
Notice where the fish was later found
Next, pay attention to the second key observation:
- In cooler, deeper waters near the island, scientists found large populations of the same fish species. So the fish did not die out completely; it just was not on the shallow reefs anymore but was present in cooler, deeper areas nearby.
Infer the logical connection between the two observations
Now connect the pieces:
- The main event mentioned is a sharp rise in water temperature.
- After that event, the fish disappeared from warmer, shallow reefs but appeared in cooler, deeper waters. A reasonable inference is that the difference in water temperature between shallow and deep areas is important for explaining where the fish went.
Match the inference to the answer choice
Look for the option that:
- Explains why the fish left the shallow reefs after the water warmed, and
- Uses the contrast between warmer shallow water and cooler deeper water to explain the new location. Only choice C, "The fish species migrated to deeper, cooler waters because it is sensitive to rising temperatures," links the temperature increase to the fish moving from warm shallows to cooler depths, directly matching the evidence in the passage.