While researching a topic, a student has taken the following notes:Stars form in a galaxy when gravity causes a massive...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
- Stars form in a galaxy when gravity causes a massive cloud of dust and gas to collapse.
- A galaxy in a phase of rapid star formation is called a starburst galaxy.
- Quenching is a process in which a galaxy loses star-forming gas.
- A galaxy that no longer forms stars is called a quenched galaxy.
- A quenched galaxy has entered the poststarburst phase.
The student wants to explain what a quenched galaxy is. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Before quenching, a starburst galaxy will form stars at a rapid rate.
When it becomes quenched, a starburst galaxy enters the poststarburst phase.
Having entered the poststarburst phase, a quenched galaxy is one that no longer forms stars.
A starburst galaxy will lose star-forming gas and eventually become quenched.
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Stars form in a galaxy when gravity causes a massive cloud of dust and gas to collapse.' |
|
| 'A galaxy in a phase of rapid star formation is called a starburst galaxy.' |
|
| 'Quenching is a process in which a galaxy loses star-forming gas.' |
|
| 'A galaxy that no longer forms stars is called a quenched galaxy.' |
|
| 'A quenched galaxy has entered the poststarburst phase.' |
|
Part B: Passage Architecture & Core Elements
Main Point: The notes trace the lifecycle of galaxies from active star formation to the end state where they no longer form stars.
Argument Flow: The notes start by establishing how stars form, then define the active phase (starburst), explain the transition process (quenching), and finally characterize the end state (quenched galaxy) both by what it lacks (no star formation) and what phase it represents (poststarburst).
Step 2: Interpret the Question Precisely
What's being asked? The student wants to explain what a quenched galaxy is, and we need to choose which option most effectively uses relevant information from the notes to accomplish this goal.
What type of answer do we need? A definition or explanation that directly characterizes what a quenched galaxy is.
Any limiting keywords? 'Most effectively uses relevant information from the notes' - so the answer must draw directly from the provided notes and do so in the most effective way for the stated purpose.
Step 3: Prethink the Answer
- To effectively explain what a quenched galaxy is, the answer should:
- Directly define or characterize quenched galaxies (not talk about other galaxy types or processes)
- Use information that's actually in the notes
- Focus on the key characteristics that distinguish quenched galaxies
- From our notes, we know that quenched galaxies have two key characteristics: they no longer form stars, and they've entered the poststarburst phase. So the right answer should use this information to directly explain what defines a quenched galaxy.
Before quenching, a starburst galaxy will form stars at a rapid rate.
✗ Incorrect
- Talks about what happens before quenching, not what a quenched galaxy is.
- Doesn't accomplish the goal of explaining quenched galaxies.
When it becomes quenched, a starburst galaxy enters the poststarburst phase.
✗ Incorrect
- Focuses on the transition process rather than defining what a quenched galaxy is.
- While it mentions both relevant concepts, it doesn't explain the characteristics of quenched galaxies.
Having entered the poststarburst phase, a quenched galaxy is one that no longer forms stars.
✓ Correct
- Directly defines what a quenched galaxy is by stating its key characteristic: 'one that no longer forms stars'.
- Effectively combines two pieces of information from the notes: the poststarburst phase and the lack of star formation.
- Accomplishes the stated goal by providing a clear explanation of quenched galaxies.
A starburst galaxy will lose star-forming gas and eventually become quenched.
✗ Incorrect
- Explains how galaxies become quenched, not what quenched galaxies are.
- Starts with starburst galaxies rather than focusing on the target concept.