( ( ( The heart ) ( is ( ( the ( ( first functional ) organ ) ) ( ( ( ( in ( vertebrate embryos ) ) , ) and ) ( in ( the human ) ) ) ) ) ) ( , ( ( ( ( beats spontaneously ) ( by week ) ) ( 4 ( of development ) ) ) . ) ) )
(ROOT (SINV (S (NP (DT The) (NN heart)) (VP (VBZ is) (NP (NP (DT the) (ADJP (JJ first) (JJ functional)) (NN organ)) (PP (PP (IN in) (NP (JJ vertebrate) (NNS embryos))) (, ,) (CC and) (PP (IN in) (NP (DT the) (NN human))))))) (, ,) (VP (VBZ beats) (ADVP (RB spontaneously)) (PP (IN by) (NP (NN week)))) (NP (NP (CD 4)) (PP (IN of) (NP (NN development)))) (. .)))
The heart is the first functional organ in vertebrate embryos, and in the human, beats spontaneously by week 4 of development.
(ROOT (S (PP (IN In) (NP (NNS humans))) (, ,) (NP (DT the) (NN heart)) (VP (VBZ is) (NP (DT the) (JJ first) (NN organ) (S (VP (TO to) (VP (VP (VB form)) (CC and) (VP (VB become) (ADJP (JJ functional)))))))) (. .)))