The mineral mtorolite is most commonly found in Zimbabwe. Mtorolite is cryptocrystalline, meaning that its crystalline structure is so fine...
GMAT Expression of Ideas : (Expression) Questions
The mineral mtorolite is most commonly found in Zimbabwe. Mtorolite is cryptocrystalline, meaning that its crystalline structure is so fine that the individual crystals cannot be distinguished by the naked eye or even under a microscope. The crystals in microcrystalline minerals are also not visible to the naked eye; _______ they can usually be seen under a microscope.
Which choice completes the text with the most logical transition?
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "The mineral mtorolite is most commonly found in Zimbabwe." |
|
| "Mtorolite is cryptocrystalline, meaning that its crystalline structure is so fine that the individual crystals cannot be distinguished by the naked eye or even under a microscope." |
|
| "The crystals in microcrystalline minerals are also not visible to the naked eye;" |
|
| "they can usually be seen under a microscope." |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: While both cryptocrystalline and microcrystalline minerals have crystals invisible to the naked eye, they differ in visibility under microscopes.
Argument Flow: The passage establishes mtorolite as cryptocrystalline, defines this as completely invisible even under microscopes, then sets up a comparison with microcrystalline minerals that share the naked-eye invisibility but can be seen under microscopic examination.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- Based on our table analysis, we need a transition that shows contrast or exception
- Before the blank, we learn that microcrystalline minerals are "also not visible to the naked eye" - this suggests similarity with cryptocrystalline
- After the blank, we learn they "can usually be seen under a microscope" - this directly contrasts with cryptocrystalline minerals that cannot be seen even under microscopes
- The relationship we need is: "Here's a similarity... BUT here's an important difference."
- So the right answer should signal contrast or concession - something that acknowledges the similarity just mentioned while introducing an important exception or difference
- "Thus" indicates causation or logical result
- Doesn't work because microscope visibility isn't a result of naked-eye invisibility
- Creates wrong logical relationship between the ideas
- "For example" introduces a specific instance of a general principle
- Doesn't work because microscope visibility isn't an example of naked-eye invisibility
- "That said" signals contrast or concession - acknowledging what was just stated while introducing an exception
- Perfect fit: acknowledges the shared naked-eye invisibility while introducing the key difference (microscope visibility)
- Matches our prethinking about needing a contrast transition
- "Similarly" indicates likeness or parallel behavior
- Wrong because microscope visibility shows difference, not similarity