( It ( ( 's ( ( tiny face ) ( ( grinning ( from ear ) ) ( to ( ear ( at ( ( the ( human ( woman 's ) ) ) ( gasped response ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ 's) (NP (NP (JJ tiny) (NN face)) (VP (VBG grinning) (PP (IN from) (NP (NN ear))) (PP (TO to) (NP (NP (NN ear)) (PP (IN at) (NP (NP (DT the) (JJ human) (NN woman) (POS 's)) (JJ gasped) (NN response)))))))) (. .)))
It's tiny face grinning from ear to ear at the human  woman's gasped response.
(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))))))))) (. .)))