( It ( ( is ( ( the pigment ) ( of ( red ( blood cells ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (NP (NP (DT the) (NN pigment)) (PP (IN of) (NP (JJ red) (NN blood) (NNS cells))))) (. .)))
It is the pigment of red blood cells.
(ROOT (S (NP (NNP Red) (NN blood) (NNS cells)) (VP (VBP are) (NP (DT the) (RBS most) (JJ numerous) (NN blood) (NNS cells))) (. .)))