The Correct Answer and Explanation is:
The correct answer is A.
Researchers have that the ridges on Europa and the ridges on Greenland may have been formed by the same process even though Europa, unlike Greenland, doesn’t have liquid water on its surface.
This choice most accurately and comprehensively captures the main idea of the provided text. The passage establishes a direct comparison between the parallel ridges on Jupiter’s moon Europa and a similar feature on Greenland’s ice sheet. The central point is the researchers’ claim that the formation mechanism is the same in both locations. The text describes this process for Greenland, where surface water seeps into cracks, freezes, expands, and forces the ice upward into ridges. It then addresses the apparent contradiction for Europa, which lacks liquid surface water. The passage resolves this by suggesting the same process could occur on Europa using water from its subsurface ocean.
Option A perfectly encapsulates this entire argument. It acknowledges the shared formation process, the two locations involved, and the critical difference regarding the presence of surface water.
The other options are incorrect for specific reasons. Option B is factually wrong according to the text, which explicitly describes the features on Europa as “parallel ridges,” just like the ones on Greenland. Option C introduces information about the timing of the ridges’ formation, a topic the passage never discusses. The text is concerned with the physical process of formation, not the geological timeline. Finally, Option D misrepresents the researchers’ position. It claims they do not understand the process, whereas the text states that they “now claim” to understand it by drawing a parallel to the Greenland ridges. It also incorrectly implies there is no known water source, ignoring the passage’s specific mention of Europa’s “subsurface ocean” as the likely origin of the water. Therefore, option A is the only choice that serves as a faithful summary of the text’s core message.
