#Productive_organs #Germ_cells #Fertilization #Cleavage #Implantation #Decidua #ProductiveOrgans #GermCells #USA #ScienceOnline #Science_online Human development starts at fertilization. Fertilization is the process by which the spermatozoon (a male gamete) and the oocyte (a female gamete) unites to give a single cell, the zygote. The spermatozoon develops in the testis and the ovum develops in the ovary.
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