( ( ( Many types ) ( of bacteria ) ) ( ( live ( as ( parasites ( on ( higher organisms ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Many) (NNS types)) (PP (IN of) (NP (NNS bacteria)))) (VP (VBP live) (PP (IN as) (NP (NP (NNS parasites)) (PP (IN on) (NP (JJR higher) (NNS organisms)))))) (. .)))
Many types of bacteria live as parasites on higher organisms.
(ROOT (S (NP (DT A) (NN hookworm)) (VP (VBZ is) (VP (VBN classified) (PP (IN as) (NP (DT a) (NN parasite))))) (. .)))
A hookworm is classified as a parasite.