( Hookworms ( ( are ( one ( of ( ( the ( ( most harmful ) ( intestinal parasite ) ) ) ( of dogs ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Hookworms)) (VP (VBP are) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT the) (ADJP (RBS most) (JJ harmful)) (JJ intestinal) (NN parasite)) (PP (IN of) (NP (NNS dogs))))))) (. .)))
Hookworms are one of the most harmful intestinal parasite of dogs.
(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.