In “the outcasts of poker flat,” what important plot development is brought on by uncle billy’s stealing of the mules?

Which sentence most needs to be revised because its description is too vague?

We hiked two miles uphill in the blooming forest today.We sprinted back and forth in the stuffy high school gym.We had to walk up several flights of stairs to get there.We stretched and then slowly jogged once around the track.

What are the options to this question