( Hookworms ( ( are ( parasites ( that ( thrive ( in ( the ( small intestine ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Hookworms)) (VP (VBP are) (NP (NP (NNS parasites)) (SBAR (WHNP (WDT that)) (S (VP (VBP thrive) (PP (IN in) (NP (DT the) (JJ small) (NN intestine)))))))) (. .)))
Hookworms are parasites that thrive in the small intestine .
(ROOT (S (NP (NNS Hookworms)) (VP (VBP infest) (NP (DT the) (NNS intestines))) (. .)))