( ( ( ( ( The ( primary consumers ) ) , ) ( who ( eat ( the plants ) ) ) ) , ) ( ( occupy ( the ( second ( trophic level ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ primary) (NNS consumers)) (, ,) (SBAR (WHNP (WP who)) (S (VP (VBP eat) (NP (DT the) (NNS plants))))) (, ,)) (VP (VB occupy) (NP (DT the) (JJ second) (JJ trophic) (NN level))) (. .)))
The primary consumers , who eat the plants, occupy the second 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)))))))) (. .)))