( ( ( ( ( ( Primary consumers ) ( -LRB- ( ( second ( trophic level ) ) -RRB- ) ) ) ( are ( herbivores ( , ( e.g. ( , ( ( cows and ) caterpillars ) ) ) ) ) ) ) ; ) ( they ( eat ( ( plants , ) ( the producers ) ) ) ) ) . )
(ROOT (S (S (NP (NP (JJ Primary) (NNS consumers)) (PRN (-LRB- -LRB-) (NP (JJ second) (JJ trophic) (NN level)) (-RRB- -RRB-))) (VP (VBP are) (NP (NNS herbivores) (, ,) (NNS e.g.) (, ,) (NNS cows) (CC and) (NNS caterpillars)))) (: ;) (S (NP (PRP they)) (VP (VBP eat) (NP (NP (NNS plants)) (, ,) (NP (DT the) (NNS producers))))) (. .)))
Primary consumers (second trophic level) are herbivores, e.g., cows and caterpillars; they eat plants, the producers.
(ROOT (S (NP (NP (JJ Secondary) (NNS consumers)) (PRN (-LRB- -LRB-) (SBAR (WHNP (WDT which)) (S (VP (VBP eat) (NP (JJ primary) (NNS consumers))))) (-RRB- -RRB-))) (VP (VBP are) (VP (VBN considered) (S (VP (TO to) (VP (VB be) (ADJP (JJ trophic) (NP (NN level) (CD 3)))))))) (. .)))