While researching a topic, a student has taken the following notes:NASA uses rovers, large remote vehicles with wheels, to explore...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
- NASA uses rovers, large remote vehicles with wheels, to explore the surface of Mars.
- NASA's rovers can't explore regions inaccessible to wheeled vehicles.
- Rovers are also heavy, making them difficult to land on the planet's surface.
- Microprobes, robotic probes that weigh as little as 50 milligrams, could be deployed virtually anywhere on the surface of Mars.
- Microprobes have been proposed as an alternative to rovers.
The student wants to explain an advantage of microprobes. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Despite being heavy, NASA's rovers can land successfully on the surface of Mars.
Microprobes, which weigh as little as 50 milligrams, could explore areas of Mars that are inaccessible to NASA's heavy, wheeled rovers.
NASA currently uses its rovers on Mars, but microprobes have been proposed as an alternative.
Though they are different sizes, both microprobes and rovers can be used to explore the surface of Mars.
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "NASA uses rovers, large remote vehicles with wheels, to explore the surface of Mars." |
|
| "NASA's rovers can't explore regions inaccessible to wheeled vehicles." |
|
| "Rovers are also heavy, making them difficult to land on the planet's surface." |
|
| "Microprobes, robotic probes that weigh as little as 50 milligrams, could be deployed virtually anywhere on the surface of Mars." |
|
| "Microprobes have been proposed as an alternative to rovers." |
|
Main Point: NASA's heavy, wheeled rovers have exploration limitations that lightweight microprobes could potentially overcome.
Step 2: Interpret the Question Precisely
What's being asked? The student's goal is to "explain an advantage of microprobes."
What type of answer do we need? This means we need an answer that clearly explains what makes microprobes better than the current approach using specific information from the notes.
Any limiting keywords? N/A
Step 3: Prethink the Answer
- From our analysis, microprobes have two clear advantages over rovers: They're extremely lightweight (50mg vs rovers being "heavy") and they can access areas that wheeled rovers cannot reach
- The strongest advantage explanation would combine these elements
Despite being heavy, NASA's rovers can land successfully on the surface of Mars.
✗ Incorrect
- States that heavy rovers can land successfully despite weight, which contradicts the notes that say weight makes rovers "difficult to land"
Microprobes, which weigh as little as 50 milligrams, could explore areas of Mars that are inaccessible to NASA's heavy, wheeled rovers.
✓ Correct
- Directly states microprobes weigh "as little as 50 milligrams" and explains they "could explore areas inaccessible to NASA's heavy, wheeled rovers"
- This perfectly combines both key advantages using specific information from notes
NASA currently uses its rovers on Mars, but microprobes have been proposed as an alternative.
✗ Incorrect
- Simply states that microprobes are "proposed as an alternative" but doesn't explain any actual advantage
Though they are different sizes, both microprobes and rovers can be used to explore the surface of Mars.
✗ Incorrect
- Says both can be used to explore Mars surface, suggesting they're equivalent rather than highlighting microprobes' advantages