( Animals ( ( ( ( are heterotrophic ) and ) ( must ( ( obtain food ) ( from ( their environment ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Animals)) (VP (VP (VBP are) (ADJP (JJ heterotrophic))) (CC and) (VP (MD must) (VP (VB obtain) (NP (NN food)) (PP (IN from) (NP (PRP$ their) (NN environment)))))) (. .)))
Animals are heterotrophic and must obtain food from their environment.
(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))))) (. .)))