( ( Stem cells ) ( ( ( are ( abundant ( in ( human ( ( embryos and ) fetuses ) ) ) ) ) ( because ( these ( are ( ( the cells ) ( that ( ( ( ( transform ( during ( embryonic development ) ) ) ( into ( various organs ) ) ) , ) ( ( ( bone and ) cartilage ) ( that ( ( make up ) ( a ( human being ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Stem) (NNS cells)) (VP (VBP are) (ADJP (JJ abundant) (PP (IN in) (NP (JJ human) (NNS embryos) (CC and) (NNS fetuses)))) (SBAR (IN because) (S (NP (DT these)) (VP (VBP are) (NP (NP (DT the) (NNS cells)) (SBAR (WHNP (WDT that)) (S (VP (VB transform) (PP (IN during) (NP (JJ embryonic) (NN development))) (PP (IN into) (NP (JJ various) (NNS organs))) (, ,) (NP (NP (NN bone) (CC and) (NN cartilage)) (SBAR (WHNP (WDT that)) (S (VP (VBP make) (PRT (RP up)) (NP (DT a) (JJ human) (NN being)))))))))))))) (. .)))
Stem cells are abundant in human embryos and fetuses because these are the cells that transform during embryonic development into various organs, bone and cartilage that make up a human being.
(ROOT (S (ADVP (RB Early) (PP (IN in) (NP (NP (DT the) (NN development)) (PP (IN of) (NP (DT a) (JJ human) (NN fetus)))))) (, ,) (NP (DT the) (NN skeleton)) (VP (VBZ is) (VP (VBN made) (ADVP (RB entirely)) (PP (IN of) (NP (NN cartilage))))) (. .)))