Dubautia carrii is a species in a family of plants known collectively as the silversword alliance, all of which grow...
GMAT Craft and Structure : (Structure) Questions
Dubautia carrii is a species in a family of plants known collectively as the silversword alliance, all of which grow only on the Hawaiian Islands. Members of this alliance exhibit an extraordinary range of phenotypes, with some species maturing into vines and others into shrubs and trees. All species in the alliance descended from a single ancestral tarweed plant that arrived on the islands around 5 million years ago. The tarweed's descendants diversified into distinct species as they adapted to live in the wide variety of habitats found on the Hawaiian Islands.
Which choice best states the main purpose of the text?
To indicate the specific tarweed ancestor of all plants that grow on the Hawaiian Islands and explain why the plants have such varied physical characteristics
To describe the specific habitat where Dubautia carrii are found and identify other plants that share a common ancestor with them
To describe the silversword alliance and explain how the plant family became so varied
To advance the claim that all plants on the Hawaiian Islands are part of the silversword alliance and list possible ancestors of the plants that make up the alliance
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Dubautia carrii is a species in a family of plants known collectively as the silversword alliance, all of which grow only on the Hawaiian Islands.' |
|
| 'Members of this alliance exhibit an extraordinary range of phenotypes, with some species maturing into vines and others into shrubs and trees.' |
|
| 'All species in the alliance descended from a single ancestral tarweed plant that arrived on the islands around 5 million years ago.' |
|
| 'The tarweed's descendants diversified into distinct species as they adapted to live in the wide variety of habitats found on the Hawaiian Islands.' |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: The passage describes the silversword alliance as a remarkably diverse group of Hawaiian plants that all evolved from a single ancestral species through adaptation to different island habitats.
Step 2: Interpret the Question Precisely
What's being asked? The main purpose of the entire text—what the passage as a whole is trying to accomplish.
What type of answer do we need? A statement that captures the central goal or function of the passage.
Any limiting keywords? N/A
Step 3: Prethink the Answer
- The passage introduces the silversword alliance and explains two key things: how remarkably diverse these plants are (vines to trees), and how this diversity came about (single ancestor adapting to different Hawaiian habitats over time)
- The right answer should mention both describing the silversword alliance and explaining how it became so varied through evolutionary adaptation
To indicate the specific tarweed ancestor of all plants that grow on the Hawaiian Islands and explain why the plants have such varied physical characteristics
✗ Incorrect
- Claims the passage identifies the specific tarweed ancestor of all plants that grow on the Hawaiian Islands
- This is too broad—the passage only discusses the silversword alliance, not ALL Hawaiian plants
To describe the specific habitat where Dubautia carrii are found and identify other plants that share a common ancestor with them
✗ Incorrect
- Claims the passage describes the specific habitat where Dubautia carrii are found
- The passage never describes where D. carrii specifically lives
- Students might focus on D. carrii since it's mentioned first, missing that it's just an entry point to discuss the alliance
To describe the silversword alliance and explain how the plant family became so varied
✓ Correct
- Accurately captures that the passage describes the silversword alliance and correctly identifies that the passage explains how the family became varied through adaptation to different habitats
To advance the claim that all plants on the Hawaiian Islands are part of the silversword alliance and list possible ancestors of the plants that make up the alliance
✗ Incorrect
- Claims the passage argues all plants on the Hawaiian Islands are part of the silversword alliance
- This is far too broad—the passage only discusses the silversword alliance specifically