Question #N1378
Although a popular theory claims that the extinction of the dinosaurs was caused by an asteroid impact, many scientists now believe that several factors contributed to their decline, ____ volcanic eruptions and climate change.
Which choice completes the text so that it conforms to the conventions of Standard English?
A. including
B. include
C. includes
D. included
Correct Answer is: A
The phrase "including volcanic eruptions and climate change" is a nonessential element that modifies the noun phrase "several factors." A comma after "decline" is needed to set off this nonessential element from the rest of the sentence.