( ( Paranasal sinuses ) ( ( are ( ( air cavities ) ( in ( ( the bones ) ( of ( ( the skull ) ( which ( connect ( to ( the ( nasal cavity ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Paranasal) (NNS sinuses)) (VP (VBP are) (NP (NP (NN air) (NNS cavities)) (PP (IN in) (NP (NP (DT the) (NNS bones)) (PP (IN of) (NP (NP (DT the) (NN skull)) (SBAR (WHNP (WDT which)) (S (VP (VBP connect) (PP (TO to) (NP (DT the) (JJ nasal) (NN cavity)))))))))))) (. .)))
Paranasal sinuses are air cavities in the bones of the skull which connect to 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))))) (. .)))