( ( Key Words ) ( plankton ( phytoplankton zooplankton ) ) )
(ROOT (NP (NP (NNP Key) (NNP Words)) (NP (NN plankton) (NN phytoplankton) (NN zooplankton))))
Key Words plankton phytoplankton zooplankton
(ROOT (S (NP (NNP Phytoplankton)) (VP (VBP make) (NP (NP (NN food)) (PP (IN via) (NP (NN photosynthesis))))) (. .)))