While researching a topic, a student has taken the following notes:In meteorology, an air mass is a large body of...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
- In meteorology, an air mass is a large body of air with generally uniform humidity and temperature.
- Air masses are commonly classified by two-letter names.
- The first letter indicates the humidity of the air mass, while the second letter indicates the temperature.
- cA (continental arctic) means dry and cold, for example.
- mT (maritime tropical) means moist and warm.
- This classification system is based on the work of a Swedish meteorologist named Tor Bergeron (1891-1977).
The student wants to provide an example of an air mass. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Air masses are large bodies of air with generally uniform humidity and temperature.
The air mass classification system uses two-letter names and is based on the work of Tor Bergeron, a Swedish meteorologist.
Air masses are commonly classified by a two-letter name that indicates humidity and temperature.
One type of air mass is known as a cA, or continental arctic, air mass because it is dry and cold.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "In meteorology, an air mass is a large body of air with generally uniform humidity and temperature." |
|
| "Air masses are commonly classified by two-letter names." |
|
| "The first letter indicates the humidity of the air mass, while the second letter indicates the temperature." |
|
| "cA (continental arctic) means dry and cold, for example." |
|
| "mT (maritime tropical) means moist and warm." |
|
| "This classification system is based on the work of a Swedish meteorologist named Tor Bergeron (1891–1977)." |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: Air masses are classified using a two-letter system that indicates their humidity and temperature characteristics.
Argument Flow: The notes start by defining what an air mass is, then explain the classification system used to categorize them, provide specific examples of how this system works, and finally give credit to the system's creator.
Step 2: Interpret the Question Precisely
What's being asked? The student wants to provide an example of an air mass, and we need to find which choice most effectively uses relevant information from the notes to accomplish this goal.
What type of answer do we need? We need a choice that actually gives a specific example of an air mass (not just general information about air masses or the classification system).
Any limiting keywords? "most effectively" and "example" are key—we need the choice that best demonstrates what an air mass actually is through a concrete instance.
Step 3: Prethink the Answer
- The right answer should present a specific type of air mass, not just general information
- Use concrete details that make the example clear and meaningful
- Draw from the specific examples provided in the research notes (cA or mT)
- Focus on one particular air mass type rather than discussing the system broadly
Air masses are large bodies of air with generally uniform humidity and temperature.
- This just restates the general definition of what air masses are
- Doesn't provide any specific example of a particular air mass
The air mass classification system uses two-letter names and is based on the work of Tor Bergeron, a Swedish meteorologist.
- Focuses on the classification system and its creator rather than giving a specific air mass example
- Provides background information but no concrete example
Air masses are commonly classified by a two-letter name that indicates humidity and temperature.
- Describes how air masses are classified in general terms
- Mentions the two-letter system but doesn't give a specific example of an actual air mass
One type of air mass is known as a cA, or continental arctic, air mass because it is dry and cold.
- Presents a specific air mass type: cA (continental arctic)
- Explains exactly what this air mass is like: dry and cold
- Uses the concrete example from the research notes to show what an air mass actually looks like in practice
- Perfectly matches the goal of providing "an example of an air mass"