( ( The ( ( lower trophic ) levels ) ) ( ( contain ( ( ( primary producers ) and ) ( primary consumers ) ) ) . ) )
(ROOT (S (NP (DT The) (ADJP (JJR lower) (JJ trophic)) (NNS levels)) (VP (VBP contain) (NP (NP (JJ primary) (NNS producers)) (CC and) (NP (JJ primary) (NNS consumers)))) (. .)))
The lower trophic levels contain primary producers and 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)))))))) (. .)))