Twins are two off springs produced in the same pregnancy. Twins can be either monozygotic ('identical'), i.,e, they develop from one zygote, which splits and forms two embryos, or dizygotic ('non-identical' or 'fraternal'), i.e., each twin develops from a separate egg that is fertilized by a separate sperm cell.
A persons‚Äô child or children OR the young one of an animal.
A zygote, also known as a fertilized ovum or fertilized egg, is formed by the union of a sperm cell and an egg cell.
An embryo is the early stage of development of a multicellular organism. Embryonic development is the part of the life cycle that begins just after fertilization and continues through the formation of body structures, such as tissues and organs, i.e., from conception to eighth week of development. After the eighth week of development, it is called the fetus until birth.