( Herbivores ( mainly ( ( eat ( the producers ) ) . ) ) )
(ROOT (S (NP (NNS Herbivores)) (ADVP (RB mainly)) (VP (VBP eat) (NP (DT the) (NNS producers))) (. .)))
Herbivores mainly eat the producers.
(ROOT (S (NP (NNS Herbivores)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (NNS animals)) (SBAR (WHNP (WDT that)) (S (VP (VBP eat) (S (NP (NNS producers)) (VP (TO to) (VP (VB get) (NP (NN energy)))))))))))) (. .)))