Final answer:
The incorrect punctuation is the use of semicolons in the sentence about the highway.
Step-by-step explanation:
The INCORRECTLY punctuated sentence is: The highway goes through cities; farmland; and prairies.
The correct way to punctuate this sentence would be: The highway goes through cities, farmland, and prairies.
The incorrect use of semicolons to separate the items in the list is the error in this sentence.
Learn more about Punctuation in English sentences