Which sentence is unrelated to the main idea? Over the decades, the United States government has designated specific places around the country for preservation and conservation. Preservation keeps something in its original state, while conservation protects it from damage. Large areas of forests, mountains, and fields have been preserved or conserved. One area is Yellowstone National Park, which covers thousands of square miles. Located in the state of California in the Sierra Nevada Mountains, Yellowstone National Park is a perfect place to take a vacation.

The sentence that is unrelated to the main idea is:

Located in the state of California in the Sierra Nevada Mountains, Yellowstone National Park is a perfect place to take a vacation.

Explanation:

After reading the passage, it is easy to see that the main idea is related to the preservation and the conservation of certain areas in the country. However, the last sentence suddenly states that Yellowstone is a perfect place to take a vacation. Even though Yellowstone was mentioned in the previous sentence, it was still in connection with the same main idea. Now, out of the blue, the writer shifts focus from the importance of preserving certain areas to how enjoyable one of them is for the holidays. Having that in mind, we can say that the sentence which is unrelated to the main idea is:

Located in the state of California in the Sierra Nevada Mountains, Yellowstone National Park is a perfect place to take a vacation.

there is no passage what do you mean?

give me the passage and i will answer your question

i believe it may be the hope this sorry if i'm wrong.