The passage below contains a blank indicating a missing punctuation mark. Read the passage and determine which punctuation mark correctly completes the sentence. In the blank provided, what punctuation mark should be placed to ensure the sentence is punctuated correctly?
Answer:Astronomers have long wondered whether other stars in the universe host planets similar to our own. The Kepler space telescope—launched in 2009 to search for Earth-size planets orbiting other stars【—】revolutionized our understanding of the galaxy by discovering thousands of exoplanets. By monitoring the brightness of over 150,000 stars, Kepler detected the tiny dips in light caused by orbiting planets passing in front of them.
Answer
A dash (—) is the correct punctuation mark to place in the blank.
A dash is correct because it matches the em dash that opens the nonessential parenthetical phrase describing the Kepler space telescope. Under standard English conventions, nonessential elements set off by dashes must be closed with a matching dash to maintain structural consistency.
Step-by-Step Solution
Key Concept
Dash Pair Consistency
Estimated Time:1m 0s