Question 124·Easy·Central Ideas and Details
The following excerpt is from a magazine article in which geologist Lena Rodriguez describes her first descent into the dormant Magdalena volcano.
I had expected heat, perhaps the faint rumble of hidden magma, but what struck me first was color. The inner walls glittered with delicate pale-green crystals that caught the sun like shards of sea glass. I ran my glove across one cluster and it crumbled into grains as fine as sugar. The sample’s tint told me more in an instant than any thermometer could: copper had once flowed here, cooling so slowly that it arranged itself into these fragile gems.
According to the passage, what does Rodriguez infer from the color of the crystals inside the volcano?
For "According to the passage" detail or inference questions, first locate the exact sentence that connects to the key word in the question (here, "color" or "tint"). Read one full sentence before and after if needed, then paraphrase in your own words what that part is saying, paying attention to time clues (past vs. future) and whether it’s about cause, result, or description. Finally, go through the answer choices and eliminate any that introduce new ideas not in the passage, contradict a detail (like "rapid" vs. "slow"), or shift the time frame, and choose the one that most directly restates the passage’s idea in different words.
Hints
Locate the key sentence
Find the sentence that mentions what the "sample’s tint" (the color) told Rodriguez. The explanation of her inference comes right after that phrase.
Focus on what kind of information she gets
Ask yourself: from the color, does she learn about the materials inside the volcano, about weather like rain, about how fast something happened, or about the volcano’s future activity?
Pay attention to past vs. future
Notice whether Rodriguez is describing something that happened in the past inside the volcano or predicting something that will happen in the future. Eliminate choices that are about the wrong time frame or not mentioned in the text.
Step-by-step Explanation
Find where the inference is stated
Look for the sentence that directly connects the color of the crystals to what Rodriguez learns from it. This is the line: "The sample’s tint told me more in an instant than any thermometer could:" — everything after the colon explains what she infers from the color.
Understand what the color reveals about the volcano
After the colon, Rodriguez explains what the tint tells her: that a particular substance had once flowed there and that it cooled slowly, forming the fragile crystals. This is information about the material inside the volcano and the way it cooled in the past, not about current rain, rapid growth, or future eruptions.
Match the passage’s idea to the answer choices
Now compare that idea to the choices:
- One option says that a specific metal was present when the crystals formed — this matches the passage’s statement that this metal had once flowed there and arranged itself into the gems.
- The other options talk about the volcano becoming active soon, recent rainwater, or crystals growing rapidly, none of which are supported (and the text actually says the material cooled "so slowly"). Therefore, the correct answer is A) Copper was present during the crystals’ formation.