Which appeal is represented by the following? "All this will not be finished in the first one hundred days. Nor will it be finished in the first one thousand days nor in the life of this Administration, nor even perhaps in our lifetime on this planet."

The appeal represented by the given statement is **ethos**, specifically establishing credibility and managing expectations. This quote is from President John F. Kennedy's inaugural address, where he emphasizes the long-term nature of the challenges ahead, thus grounding his administration's promises in reality and demonstrating honesty and humility.