Answer:
Jack said there was a dog that was a high-flying, nineteenth-century trapeze artist; his claim is intriguing, yet highly unlikely.
Explanation:
Hyphens are used when there is a need to form a compound adjective that comes before a noun. This enables the compound adjective to modify or describe the noun that follows. But when the compound adjective comes after a noun, then there is no need to hyphenate the word.
In the given sentence, the words "high flying" and "nineteenth century" are used to describe the word "artist" which is a noun. Therefore, they are hyphenated to make a compound adjective and help describe the artist dog,
Thus, the final sentence will be written as-
<u><em>Jack said there was a dog that was a high-flying, nineteenth-century trapeze artist; his claim is intriguing, yet highly unlikely.</em></u>
