Question 143·Medium·Transitions
Many oceanographers once believed that the deep seafloor was a barren expanse devoid of life. ______, the discovery of hydrothermal vents in the late 1970s revealed thriving ecosystems of tube worms, mussels, and bacteria at extreme depths.
Which choice completes the text with the most logical transition?
For transition questions, always read the sentence before and after the blank together and decide the exact relationship between the ideas (contrast, cause/effect, example, addition, sequence, etc.) before looking closely at the choices. Then eliminate any options whose typical function (example, similarity, addition, contrast) does not match that relationship, and choose the one whose meaning fits the logic of the passage, not just what “sounds right.”
Hints
Summarize each sentence
Briefly restate the idea before the blank and the idea after it in your own words. Are they about the same thing? Does one change or challenge the other?
Check how the second idea relates to the first
Ask yourself: Does the discovery mentioned after the blank support the earlier belief, give an example of it, add more of the same kind of information, or show that the earlier belief was not correct?
Think about the function of each type of transition
Consider what each kind of transition word does: one introduces examples, one shows similarity, one adds another point, and one shows a difference or contrast. Which function matches the relationship you found between the two parts?
Step-by-step Explanation
Understand what each part of the sentence is saying
Read the two ideas without worrying about the blank:
- First part: Oceanographers once believed the deep seafloor was a barren, lifeless place.
- Second part: A later discovery showed thriving ecosystems of different organisms at extreme depths.
So the first part gives an old belief; the second part gives a discovery about what the seafloor is actually like.
Identify the logical relationship between the two ideas
Ask: Does the second idea support, repeat, give an example of, or go against the first idea?
- The old belief: no life on the deep seafloor.
- The new discovery: lots of life on the deep seafloor.
The discovery contradicts the old belief; it shows that earlier scientists were wrong about the seafloor being barren. This is a contrast relationship between a past belief and new evidence.
Match the relationship to the type of transition
Now look at the answer choices and think about the kind of connection each one usually shows:
- "For example" introduces a specific instance of a general idea.
- "Similarly" shows that two ideas are alike.
- "In addition" adds another point in the same direction.
- "However" shows contrast or an unexpected difference.
Because the second idea goes against the first, we need the transition that signals contrast: C) However.