The Sun and other stars are powered by nuclear fusion reactions, in which two atoms collide to form a single...
GMAT Expression of Ideas : (Expression) Questions
The Sun and other stars are powered by nuclear fusion reactions, in which two atoms collide to form a single heavier atom, releasing energy. Scientists have long believed that fusion has the potential to meet humanity's clean energy needs. ________ prior to December 2022, no fusion reaction in a laboratory setting had ever generated a net energy gain.
Which choice completes the text with the most logical transition?
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'The Sun and other stars are powered by nuclear fusion reactions, in which two atoms collide to form a single heavier atom, releasing energy.' |
|
| 'Scientists have long believed that fusion has the potential to meet humanity's clean energy needs.' |
|
| [MISSING TRANSITION] |
|
| 'prior to December 2022, no fusion reaction in a laboratory setting had ever generated a net energy gain.' |
|
Part B: Passage Architecture & Core Elements
Main Point: While scientists have long been optimistic about fusion's potential for clean energy, actual laboratory success in achieving net energy gain remained elusive until December 2022.
Argument Flow: The passage establishes fusion as a natural stellar process, presents scientific optimism about its clean energy potential, then reveals the gap between that optimism and laboratory reality prior to a recent breakthrough.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- We have scientific optimism about fusion's potential, followed by the reality that no lab had achieved net energy gain before December 2022
- The blank needs to show contrast or acknowledgment that despite the optimism, there was a significant limitation
- The connector should signal contrast - acknowledging the previous positive view while introducing a contrasting reality
- Implies causation, suggesting the laboratory limitation happened because of fusion's potential
- This doesn't make logical sense
- Adds similar or supporting information rather than contrasting information
- Would suggest the laboratory limitation supports the optimism, which is illogical
- Introduces a specific example about the previous statement
- Would suggest that 'no net energy gain' is a specific example of fusion's potential, which is backwards
- Shows contrast by acknowledging the previous statement while introducing a limitation
- Perfectly captures the 'despite the optimism, here's the reality' relationship