( ( Consumers ( that ( only ( eat plants ) ) ) ) ( ( are ( called herbivores ) ) . ) )
(ROOT (S (NP (NP (NNS Consumers)) (SBAR (WHNP (WDT that)) (S (ADVP (RB only)) (VP (VBP eat) (NP (NNS plants)))))) (VP (VBP are) (VP (VBN called) (NP (NNS herbivores)))) (. .)))
Consumers that only eat plants are called herbivores.
(ROOT (S (NP (NNS Herbivores)) (VP (VBP are) (NP (NP (NNS heterotrophs)) (SBAR (WHNP (WDT that)) (S (VP (VBP eat) (NP (UCP (ADJP (JJ only)) (CC or) (ADVP (RB mainly))) (NNS plants))))))) (. .)))