PrepTest 133, Section 4, Question 16
Until the 1950s, most scientists believed that the(440 more words not shown)
Which one of the following(9 more words not shown)
- AIn the 1950s,(19 more words not shown)
- BThe discovery of(23 more words not shown)
- CIn the 1950s,(16 more words not shown)
- DLocal distortions to(23 more words not shown)
- EThe discovery of(28 more words not shown)
Reading the passage
We've already predicted the main idea: the ocean floor changes over time, and the magnetic evidence and mid-ocean ridge helped scientists recognize that. We're looking for the change in understanding, not just one interesting fact about magnets.
Working the answers
- A
This frames the discussion as refining an account of how the floor formed long ago. The important change is abandoning the idea that it has remained essentially unchanged: new crust continues to form and spread. A misses that shift.
- B
Basalt's magnetic properties were already known. The new finding was the ocean floor's magnetic variations and their pattern. B also narrows the point to explaining stripes, while the stripes support the larger change in geological understanding.
- CCorrect
The magnetic variations and the mid-ocean ridge are the two discoveries. They helped overturn the static view and support ocean floor spreading. This captures our prediction about transformed scientific understanding without having to repeat every step of the theory.
- D
Compass distortion is background for the magnetic discussion, not the central conclusion about the ocean floor. This answer leaves out the change in scientific views.
- E
More mapping revealed patterns, but we aren't told that magnetic variations convinced scientists to map the entire floor. That proposed decision and sequence aren't the main idea.
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