( ( ( Secondary consumers ) ( -LRB- ( ( third ( trophic level ) ) -RRB- ) ) ) ( ( eat ( primary consumers ) ) . ) )
(ROOT (S (NP (NP (JJ Secondary) (NNS consumers)) (PRN (-LRB- -LRB-) (NP (JJ third) (JJ trophic) (NN level)) (-RRB- -RRB-))) (VP (VBP eat) (NP (JJ primary) (NNS consumers))) (. .)))
Secondary consumers (third trophic level) eat primary consumers.
(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)))))))) (. .)))