( aphotic ( ( zone ( ( The portion ) ( of ( ( the ocean ) ( where ( ( ( the absence ) ( of sunlight ) ) ( prohibits ( plant growth ) ) ) ) ) ) ) ) . ) )
(ROOT (SINV (ADJP (JJ aphotic)) (VP (VBZ zone)) (NP (NP (DT The) (NN portion)) (PP (IN of) (NP (NP (DT the) (NN ocean)) (SBAR (WHADVP (WRB where)) (S (NP (NP (DT the) (NN absence)) (PP (IN of) (NP (NN sunlight)))) (VP (VBZ prohibits) (NP (NN plant) (NN growth)))))))) (. .)))
aphotic zone The portion of the ocean where the absence of sunlight prohibits plant growth.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT the) (JJ lightless) (NN part)) (PP (IN of) (NP (DT the) (NN ocean) (JJ aphotic) (NN zone))))) (. .)))