I am not sure if you are doing the same quiz as the other girl but this was her answer: Like a pig or a dog with ultra-sensitive nasal hairs, he was trying to pick up a scent. "He could smell something". Alternatively, his nostrils quivered as he took in air in readiness for an action, so possibly a preparation for an act of aggression.
Another Answer: My cheek had grown pale with study and my person had become emaciated with confinement) your welcome
I think that it was because he admired what he saw as the strong rebelliousness of a pioneer woman.
