Question 159·Hard·Transitions
Geophysicist Maria Zuber notes that Mercury’s surface is heavily cratered, suggesting that the planet has been geologically inactive for billions of years. ______ evidence from the MESSENGER spacecraft indicates that Mercury’s interior is still slowly contracting, periodically wrinkling the crust to form new ridges.
Which choice completes the text with the most logical transition?
For transition questions, always read at least one full sentence before and after the blank and summarize each idea in simple words. Decide the relationship between them—same direction, contrast, cause-and-effect, or simple addition—before looking closely at the choices. Then quickly label each option by its function (similarity, contrast, cause/effect, addition) and eliminate any whose function does not match the relationship you identified. Plug the remaining option into the sentence to confirm that it makes both logical and stylistic sense.
Hints
Identify the main point before and after the blank
Restate, in your own words, what Zuber says about Mercury before the blank and what the MESSENGER evidence shows after the blank. Are those two ideas the same, or different?
Think about the logical relationship
Ask: Does the MESSENGER evidence back up Zuber’s conclusion, explain it, or make it seem less certain or even wrong?
Match relationship to transition types
Look at the four options and classify each one as either showing similarity, cause-and-effect, addition, or contrast. Then pick the one whose type matches the relationship you noticed between the two ideas.
Step-by-step Explanation
Understand each part of the sentence
Paraphrase the two ideas:
- First part: Mercury’s surface is heavily cratered, so scientists think it has been geologically inactive for a very long time.
- Second part: New evidence from the MESSENGER spacecraft shows Mercury’s interior is still slowly contracting, forming new ridges. These are two different scientific claims about Mercury.
Decide how the ideas are related
Ask yourself: Does the second idea support, explain, or repeat the first idea, or does it go against it?
- The first idea: Mercury seems geologically inactive.
- The second idea: Mercury is still changing internally (which suggests geological activity). These two ideas conflict with each other: an apparently inactive planet is actually still active inside.
Match the relationship to a transition type
Now connect the relationship you found to the transition types:
- A word showing similarity would be used if the second idea supported or repeated the first.
- A word showing cause and effect would be used if the second idea were a result of the first.
- A word showing addition would be used if the second idea added another, similar point.
- A word showing contrast would be used if the second idea went against or surprised the first. Because the two ideas conflict, you need a contrast transition.
Evaluate the answer choices
Identify which choice signals contrast:
- "Similarly," signals similarity.
- "As a result," signals cause and effect.
- "Moreover," signals addition of similar information.
- "However," signals contrast between two opposing or surprising ideas. Only A) However, correctly shows the contrast between Mercury appearing geologically inactive and new evidence that it is still changing inside.