( Heterotrophs ( ( must ( ( feed ( on ( other organisms ) ) ) ( to ( obtain energy ) ) ) ) . ) )
(ROOT (S (NP (NNS Heterotrophs)) (VP (MD must) (VP (VB feed) (PP (IN on) (NP (JJ other) (NNS organisms))) (S (VP (TO to) (VP (VB obtain) (NP (NN energy))))))) (. .)))
Heterotrophs must feed on other organisms to obtain energy.
(ROOT (S (NP (NP (NNS Organisms)) (ADJP (JJ incapable) (PP (IN of) (NP (NP (NN photosynthesis)) (SBAR (WHNP (WDT that)) (S (VP (MD must) (ADVP (RB therefore)) (VP (VB obtain) (NP (NN energy) (CC and) (NN carbon)) (PP (IN from) (NP (NN food))) (PP (IN by) (S (VP (VBG consuming) (NP (JJ other) (NNS organisms))))))))))))) (VP (VBP are) (VP (VBN called) (NP (NNS heterotrophs)))) (. .)))