( It ( ( was ( designed ( to ( approximate ( ( the response ) ( of ( the ( human ( ear ( to sound ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBD was) (VP (VBN designed) (S (VP (TO to) (VP (JJ approximate) (NP (NP (DT the) (NN response)) (PP (IN of) (NP (DT the) (JJ human) (NN ear) (S (VP (TO to) (VP (VB sound)))))))))))) (. .)))
It was designed to approximate the response of the human ear to sound.
(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))))))))) (. .)))