( ( hundreds ( of ( ( ( ( ( ( star clusters ) , ) nebulae ) , ) and ) galaxies ) ) ) ; )
(ROOT (NP (NP (NNS hundreds)) (PP (IN of) (NP (NP (NN star) (NNS clusters)) (, ,) (NP (NN nebulae)) (, ,) (CC and) (NP (NNS galaxies)))) (: ;)))
hundreds of star clusters, nebulae, and galaxies;
(ROOT (S (NP (DT A) (NN galaxy)) (VP (VBZ is) (VP (RBS best) (VBN described) (PP (IN as) (NP (NP (DT a) (NN cluster)) (PP (IN of) (NP (NP (NNS billions)) (PP (IN of) (NP (NNS stars))))))))) (. .)))