( ( Paramecium bursaria ) ( ( is ( ( a member ) ( of ( ( a ( large group ) ) ( of ( ( ( ( ( ( complex , ) but ) ( single celled ) ) , ) protists ) ( -LRB- ( eukaryotes -RRB- ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Paramecium) (NNP bursaria)) (VP (VBZ is) (NP (NP (DT a) (NN member)) (PP (IN of) (NP (NP (DT a) (JJ large) (NN group)) (PP (IN of) (NP (NP (ADJP (ADJP (JJ complex)) (, ,) (CC but) (ADJP (JJ single) (JJ celled)) (, ,)) (NNS protists)) (PRN (-LRB- -LRB-) (NP (NNS eukaryotes)) (-RRB- -RRB-)))))))) (. .)))
Paramecium bursaria is a member of a large group of complex, but single celled, protists (eukaryotes).
(ROOT (S (NP (NNS Scientists)) (VP (VBP think) (SBAR (S (NP (NNS protists)) (VP (VBP are) (NP (DT the) (JJS oldest) (NNS eukaryotes)))))) (. .)))