Question 5·Medium·Transitions
A century ago, biologists believed that certain species of Galápagos finches were completely isolated on their respective islands. ______ subsequent genetic analyses have revealed that the birds occasionally cross the narrow channels between islands, exchanging genes and maintaining a surprising degree of connectivity.
Which choice completes the text with the most logical transition?
For transition questions, always read a bit before and after the blank and summarize, in simple words, how the two ideas relate (agree, disagree, cause–effect, example, sequence, etc.). Then eliminate any choices that signal the wrong type of relationship, even if they sound smooth. Focus on meaning, not on what “sounds good,” and pick the transition whose function (contrast, similarity, result, sequence) best matches the relationship you identified.
Hints
Compare the two halves of the sentence
Read carefully what scientists used to believe and what the genetic analyses now show. Ask yourself: do these two parts agree, or do they clash in some way?
Think about the effect of the new evidence
Does the new genetic evidence simply continue the old belief, explain a result of it, or show something unexpected compared to that belief?
Match the relationship to the transition type
Decide whether the sentence needs a transition that shows similarity, cause-and-effect, a simple sequence in time, or an unexpected contrast between old and new information.
Step-by-step Explanation
Understand the first idea
Read the part before the blank: "A century ago, biologists believed that certain species of Galápagos finches were completely isolated on their respective islands." This describes an old belief: the finches were thought to be completely isolated on separate islands.
Understand the second idea
Now read the part after the blank: "subsequent genetic analyses have revealed that the birds occasionally cross the narrow channels between islands, exchanging genes and maintaining a surprising degree of connectivity." This says that newer genetic data shows the finches do move between islands and share genes, so they are not completely isolated.
Determine the logical relationship
Compare the two ideas:
- Old belief: complete isolation.
- New evidence: birds cross between islands and are connected.
The second idea does not support or continue the first; instead, it goes against or reverses that belief by showing a different reality.
Match the relationship to the best transition
Now check each option:
- "Similarly," would show that the second idea is like the first.
- "Consequently," would show a result of the first idea.
- "Next," would show a simple time or step sequence.
- "However," shows that what comes next contrasts with or qualifies what came before.
Because the new genetic evidence contradicts the old belief about isolation, the transition that shows contrast—"However,"—is the most logical choice.