Genetic studies have led researchers to suggest that turtles are most closely related to the group that includes modern crocodiles....
GMAT Craft and Structure : (Structure) Questions
Genetic studies have led researchers to suggest that turtles are most closely related to the group that includes modern crocodiles. But studies of fossils have suggested instead that turtles are most closely related to other groups, such as the one that contains modern snakes. However, many of the fossil studies have relied on incomplete data sets. For a 2022 investigation, biologist Tiago R. Simões and colleagues examined more than 1,000 reptile fossils collected worldwide. From this large data set, they found clear agreement with the results of the genetic studies.
Which choice best describes the function of the underlined sentence?
It offers an overview of the tools scientists use to examine fossils.
It describes a limitation of some studies about the origin of turtles.
It summarizes previous research on the evolution of crocodiles.
It criticizes a widely held belief about genetic studies of reptiles.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Genetic studies have led researchers to suggest that turtles are most closely related to the group that includes modern crocodiles.' |
|
| 'But studies of fossils have suggested instead that turtles are most closely related to other groups, such as the one that contains modern snakes.' |
|
| 'However, many of the fossil studies have relied on incomplete data sets.' |
|
| 'For a 2022 investigation, biologist Tiago R. Simões and colleagues examined more than 1,000 reptile fossils collected worldwide.' |
|
| 'From this large data set, they found clear agreement with the results of the genetic studies.' |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: A comprehensive 2022 fossil study resolved the conflict between genetic and fossil evidence about turtle evolution by supporting the genetic findings.
Argument Flow: The passage presents two competing scientific views about turtle relationships, then identifies a weakness in the fossil-based research (incomplete data), and finally describes how a more thorough fossil study resolved the conflict in favor of the genetic evidence.
Step 2: Interpret the Question Precisely
What's being asked? The function of the underlined sentence in the passage
What type of answer do we need? A description of what role that specific sentence plays in the passage's structure
Any limiting keywords? 'Function' tells us we need to identify the sentence's job or purpose, not just what it says
Step 3: Prethink the Answer
- The underlined sentence comes right after we learn about conflicting findings between genetic and fossil studies
- The sentence explains that 'many of the fossil studies have relied on incomplete data sets'
- This is clearly pointing out a weakness or flaw in the fossil studies that were just mentioned
- The correct answer should describe this sentence as identifying a limitation or weakness in the fossil studies that were just discussed
It offers an overview of the tools scientists use to examine fossils.
✗ Incorrect
- This choice suggests the sentence discusses tools for examining fossils
- The sentence talks about 'incomplete data sets,' not tools or methods
It describes a limitation of some studies about the origin of turtles.
✓ Correct
- This perfectly captures what the sentence does - it describes a limitation (incomplete data sets) of fossil studies about turtle origins
- 'Limitation' accurately describes how incomplete data sets would weaken the fossil studies' conclusions
It summarizes previous research on the evolution of crocodiles.
✗ Incorrect
- The sentence doesn't mention crocodile evolution at all
- The passage discusses turtle evolution and their relationship to other groups
It criticizes a widely held belief about genetic studies of reptiles.
✗ Incorrect
- The sentence doesn't criticize genetic studies - it actually sets up why fossil studies might be less reliable
- The passage ultimately supports genetic studies through the 2022 research