( Progesterone ( ( is ( ( ( ( produced , ) ( after ovulation ) ) , ) ( by ( ( the cells ) ( of ( the ( corpus luteum ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Progesterone)) (VP (VBZ is) (VP (VBN produced) (, ,) (PP (IN after) (NP (NN ovulation))) (, ,) (PP (IN by) (NP (NP (DT the) (NNS cells)) (PP (IN of) (NP (DT the) (NN corpus) (NN luteum))))))) (. .)))
Progesterone is produced, after ovulation, by the cells of the corpus luteum.
(ROOT (S (NP (NP (DT The) (NNS cells)) (PP (IN in) (NP (DT the) (NN follicle)))) (VP (VP (VBP undergo) (NP (JJ physical) (NNS changes))) (CC and) (VP (VBP produce) (SBAR (S (NP (DT a) (NN structure)) (VP (VBD called) (NP (DT a) (NN corpus) (NN luteum))))))) (. .)))