Choose the word or set of words that, when inserted in the sentence, best fits the meaning of the sentence as a whole.

Currently rising temperatures in the Arctic and Antarctic are ------- of a still warmer world that could result from an excess of atmospheric carbon dioxide produced by the burning of oil, gas, and coal.

1. polarities
   
   
2. harbingers
   
   
3. vestiges
   
   
4. counterexamples
   
   
5. aftereffects

Correct Answer: B

Here's Why:

A harbinger is a sign of something yet to come. Temperatures are presented as “harbingers” in this sentence because they show that “a still warmer world” might be coming.

Difficulty: Hard

Question Type: Sentence Completions