( ( Filter ( ( the air ) ( entering ( the ( nasal cavity ) ) ) ) ) . )
(ROOT (S (VP (VB Filter) (NP (NP (DT the) (NN air)) (VP (VBG entering) (NP (DT the) (JJ nasal) (NN cavity))))) (. .)))
Filter the air entering the nasal cavity.
(ROOT (S (PP (IN In) (NP (NNS mammals))) (, ,) (NP (NN air)) (VP (VBZ is) (VP (VBN warmed) (CC and) (VBN humidified) (PP (IN in) (NP (DT the) (JJ nasal) (NN cavity))))) (. .)))