( ( ( ( ( ( The ( unusual features ) ) ( of ( the opalines ) ) ) , ) ( first ( observed ( by ( ( Antoine ( van Leeuwenhoek ) ) ( in 1683 ) ) ) ) ) ) , ) ( ( has ( led ( to ( ( much debate ) ( regarding ( ( their ( phylogenetic position ) ) ( among ( the protists ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ unusual) (NNS features)) (PP (IN of) (NP (DT the) (NNS opalines))) (, ,) (VP (ADVP (RB first)) (VBN observed) (PP (IN by) (NP (NP (NNP Antoine) (NNP van) (NNP Leeuwenhoek)) (PP (IN in) (NP (CD 1683)))))) (, ,)) (VP (VBZ has) (VP (VBN led) (PP (TO to) (NP (NP (JJ much) (NN debate)) (PP (VBG regarding) (NP (NP (PRP$ their) (JJ phylogenetic) (NN position)) (PP (IN among) (NP (DT the) (NNS protists))))))))) (. .)))
The unusual features of the opalines, first observed by Antoine van Leeuwenhoek in 1683, has led to much debate regarding their phylogenetic position among the protists.
(ROOT (S (NP (JJ Multiple) (NN fission)) (VP (VBZ is) (ADVP (RBR more) (RB often)) (VP (VBN observed) (PP (IN among) (NP (NNS protists))))) (. .)))