Final answer:
The sentence punctuated incorrectly is: The author who is speaking today has written several works on historical subjects, including: the Civil War, the French Revolution, and the exploration of the Arctic.
Step-by-step explanation:
The sentence punctuated incorrectly is:
The author who is speaking today has written several works on historical subjects, including: the Civil War, the French Revolution, and the exploration of the Arctic.
The incorrect punctuation is the use of a colon after 'including'. A colon is used to introduce a list, but in this case, the sentence is already introducing a list, so the colon is unnecessary and should be removed.
Learn more about punctuation in English sentences