The next two passages have the topic sentence underlined. With that controlling idea in mind, find the one sentence that has been inserted that does not belong there because it breaks the unity. Cross out or highlight the sentence. An overwhelming light swept me.

My resolution was instantaneous. I would do the same. I would make my legs strong on the foothills. Thus I started my treks and used the foothills as one uses weights or bars in a gymnasium. These early hikes put me on intimate terms with the hills. First I tried to go up the hills without stopping. When I conquered that, I tried to go up without a change of pace. When that was achieved, I practiced going up not only without a change of pace but whistling as I went.