( ( The other ) ( ( is ( to ( balance ( ( the pressure ) ( between ( ( ( the ( inner ear ) ) and ) ( the ( external environment ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ other)) (VP (VBZ is) (S (VP (TO to) (VP (VB balance) (NP (NP (DT the) (NN pressure)) (PP (IN between) (NP (NP (DT the) (JJ inner) (NN ear)) (CC and) (NP (DT the) (JJ external) (NN environment))))))))) (. .)))
The other is to balance the pressure between the inner ear and the external environment.
(ROOT (S (NP (DT The) (NNS ears)) (VP (VBP are) (NP (NP (DT an) (JJ external) (NN feature)) (PP (IN in) (NP (JJ human) (NNS beings))) (SBAR (S (VP (VBZ is) (ADJP (JJ responsible) (PP (IN for) (NP (NN balance))))))))) (. .)))