( ( ( The stars ) ( in ( elliptical galaxies ) ) ) ( ( are ( old ( ( Population II ) stars ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS stars)) (PP (IN in) (NP (JJ elliptical) (NNS galaxies)))) (VP (VBP are) (ADJP (JJ old) (SBAR (S (NP (NNP Population) (NNP II)) (VP (VBZ stars)))))) (. .)))
The stars in elliptical galaxies are old Population II stars.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (JJ egg-shaped) (NNS galaxies)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP are) (ADJP (JJ reddish) (S (VP (TO to) (VP (VB yellowish) (PP (IN in) (NP (NN color))) (SBAR (IN because) (S (NP (PRP they)) (VP (VBP contain) (NP (NP (ADJP (RB mostly) (JJ old)) (NNS stars)) (, ,) (NP (JJ elliptical) (NNS galaxies))))))))))))))) (. .)))