( ( The ( menstrual cycle ) ) ( ( is ( ( ( the cycle ) ( of ( natural changes ) ) ) ( that ( occurs ( in ( ( the ( ( uterus and ) ovary ) ) ( as ( ( an ( essential part ) ) ( of ( making ( ( sexual reproduction ) possible ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ menstrual) (NN cycle)) (VP (VBZ is) (NP (NP (DT the) (NN cycle)) (PP (IN of) (NP (JJ natural) (NNS changes))) (SBAR (WHNP (WDT that)) (S (VP (VBZ occurs) (PP (IN in) (NP (NP (DT the) (NN uterus) (CC and) (NN ovary)) (PP (IN as) (NP (NP (DT an) (JJ essential) (NN part)) (PP (IN of) (S (VP (VBG making) (S (NP (JJ sexual) (NN reproduction)) (ADJP (JJ possible))))))))))))))) (. .)))
The menstrual cycle is the cycle of natural changes that occurs in the uterus and ovary as an essential part of making sexual reproduction possible.
(ROOT (S (NP (NNP Ovulation)) (VP (VP (VBZ takes) (NP (NN place)) (PP (IN in) (NP (DT the) (NN ovary)))) (CC and) (VP (VBZ is) (NP (NP (NN part)) (PP (IN of) (NP (DT the) (JJ menstrual) (NN cycle)))))) (. .)))