( ( Human ( ( are normally ) heterotroph ) ) ( , ( it ( ( means ( that ( they ( need ( ( material source ) ( of ( food ( -LRB- ( ( other organisms ) -RRB- ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (NNP Human)) (VP (VBP are) (ADVP (RB normally)) (ADJP (JJ heterotroph)))) (, ,) (NP (PRP it)) (VP (VBZ means) (SBAR (IN that) (S (NP (PRP they)) (VP (VBP need) (NP (NP (NN material) (NN source)) (PP (IN of) (NP (NP (NN food)) (PRN (-LRB- -LRB-) (NP (JJ other) (NNS organisms)) (-RRB- -RRB-))))))))) (. .)))
Human are normally heterotroph, it means that they need material source of food (other organisms).
(ROOT (S (SBAR (IN Because) (S (NP (DT all) (NNS animals)) (VP (VBP require) (NP (NP (DT an) (JJ external) (NN source)) (PP (IN of) (NP (NN food))))))) (, ,) (NP (PRP they)) (VP (VBP are) (VP (VBN called) (S (ADJP (JJ heterotrophic))))) (. .)))