Answer: Jefferson was both the writer of the declaration of independence and the nation's third president.
Step-by-step explanation:
Faulty parallelism is also known as a parallel construction error. It occurs in sentences that contain lists, when grammatical structures within a sentence are not parallel. In other words, two or more parts of the sentence might be similar in meaning, but different in form.
In the second part of this sentence - Jefferson was both the writer of the declaration of independence and he was the nation's third president, 'he was' must be omitted. We already have the verb 'to be' at the beginning of the sentence that serves as an introduction to a list that follows, and encompasses both the phrase 'the writer of the declaration of independence' and 'the nation's third president.' It is, therefore, not grammatically correct to repeat the subject and the verb once again.