dizygotic and monozygotic twins

amniotic anatomy baby biology birth care cell child development diagram different diploid dizygotic egg embryo embryology female fertile fertility fertilization fetal fetus follicle fraternal fusion gametes genetic genetically growth gynecology haploid health human identical illustration individuals infant infertility insemination isolated life medical medicine model monozygotic mother newborn nucleus oocyte ovulation ovum placenta plus pregnancy pregnant prenatal reproduction reproductive sac science separate sperm spermatozoon stage structure twins umbilical unborn vector woman zygote