Question

as she gazed across the plane, a smell filled her nostrils which phrase can replace now to get the sentence a peaceful cone would it be clean scent, foul odor, sickening stink, putrid, stink

Answer 1

To convey a peaceful tone in the sentence, "a clean scent" would be the best choice to replace "smell." Here's the revised sentence:

"As she gazed across the plain, a clean scent filled her nostrils."