Complex sentence: "Mont Blanc" compares the power of the mountain to that of the human imagination; while emphasizing the ability of the human imagination to uncover truth through a study of nature, Shelley also questions religious certainty.
Split into simpler sentences: Mont Blanc compares the power of the mountain to that of the human imagination. While emphasizing the ability of the human imagination to uncover truth through a study of nature, Shelley questions religious certainty.