( It ( ( ( is therefore ) ( possible ( to ( look ( at ( ( the ( cell ( cycle profile ) ) ) ( of ( four ( phenotypically-defined populations ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (ADVP (RB therefore)) (ADJP (JJ possible) (S (VP (TO to) (VP (VB look) (PP (IN at) (NP (NP (DT the) (NN cell) (NN cycle) (NN profile)) (PP (IN of) (NP (CD four) (JJ phenotypically-defined) (NNS populations)))))))))) (. .)))
It is therefore possible to look at the cell cycle profile of four phenotypically-defined populations.
(ROOT (S (NP (NNS Cells)) (VP (VBP have) (NP (CD four) (NNS cycles))) (. .)))