(I) The Human female reproductive system which produces eggs is Ovary
(II) The human female reproductive system where fusion of egg and sperm takes place is Fallopian tube.
(III) The human female reproductive system where zygote is implanted is Uterus.
The diagram is as follows:
If the egg is not fertilized, then the thick and soft inner lining along with the dead egg and blood vessels, of uterus gets out of vagina in bleeding form. This process is known as Menstruation. It occurs when sperms are not available in female body