( ( Meaning they ) ( ( ( eat plants ) only ) . ) )
(ROOT (S (S (VP (VBG Meaning) (NP (PRP they)))) (VP (VBP eat) (NP (NNS plants)) (ADVP (RB only))) (. .)))
Meaning they eat plants only.
(ROOT (S (NP (DT The) (NN heterotroph)) (VP (VBZ eats) (NP (UCP (ADJP (JJ only)) (CC or) (ADVP (RB mainly))) (NNS plants))) (. .)))