Containing over 160 billion base pairs of DNA resulting from polyploidy (whole genome duplication) and accumulation of noncoding DNA without...
GMAT Craft and Structure : (Structure) Questions
Containing over 160 billion base pairs of DNA resulting from polyploidy (whole genome duplication) and accumulation of noncoding DNA without significant deletion, the genome of Tmesipteris oblanceolata (New Caledonian fork fern) is the largest known among eukaryotes - and, given the high biological costs of extremely large genomes, is unlikely to be _______.
Which choice completes the text with the most logical and precise word or phrase?
protracted
superseded
curtailed
obviated
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Containing over 160 billion base pairs of DNA resulting from polyploidy (whole genome duplication) and accumulation of noncoding DNA without significant deletion," |
|
| "the genome of Tmesipteris oblanceolata (New Caledonian fork fern) is the largest known among eukaryotes" |
|
| "—and, given the high biological costs of extremely large genomes," |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: The New Caledonian fork fern holds the record for largest eukaryotic genome, but biological costs make this record unlikely to be surpassed.
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
- The passage sets up that this fern has the largest known genome, but then introduces the key fact that extremely large genomes have high biological costs
- The biological costs would discourage other organisms from evolving even larger genomes
- So this record is likely to stand because it would be disadvantageous for other species to develop even larger genomes
- The right answer should indicate that this record won't be broken or replaced
protracted
protracted ✗ Incorrect
- "Protracted" means prolonged or extended over time
- This doesn't fit the logical relationship - we're not talking about the genome being extended in duration, but rather about whether this size record will be broken
superseded
superseded ✓ Correct
- "Superseded" means replaced or surpassed by something better
- Fits perfectly - because large genomes have high biological costs, it's unlikely another organism will evolve an even larger genome to replace this record
curtailed
curtailed ✗ Incorrect
- "Curtailed" means reduced or cut short
- This would suggest the genome itself might be reduced, but that doesn't connect logically to the "high biological costs"
obviated
obviated ✗ Incorrect
- "Obviated" means made unnecessary or eliminated
- Doesn't create a logical connection between biological costs and the genome's record status