( ( ( An organism ) ( that ( feeds ( on ( a ( secondary consumer ) ) ) ) ) ) ( ( is ( called ( ( a ( tertiary consumer ) ) ( -LRB- ( ( fourth ( trophic level ) ) -RRB- ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT An) (NN organism)) (SBAR (WHNP (WDT that)) (S (VP (VBZ feeds) (PP (IN on) (NP (DT a) (JJ secondary) (NN consumer))))))) (VP (VBZ is) (VP (VBN called) (NP (NP (DT a) (JJ tertiary) (NN consumer)) (PRN (-LRB- -LRB-) (NP (JJ fourth) (JJ trophic) (NN level)) (-RRB- -RRB-))))) (. .)))
An organism that feeds on a secondary consumer is called a tertiary consumer (fourth trophic level).
(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)))))))) (. .)))