If the flasks were left sealed for a week, which one would
most likely have the largest amount of CO2?

they are known to reach a speed of 21 miles per hour

the answer is d. none of the above

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.