Embryo
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An embryo is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilizati
A human embryo seven weeks after conception (nine weeks gestational age)
Embryos (and one tadpole) of the wrinkled frog (Rana rugosa)
Mouse and snake embryos
The inside of a Ginkgo seed, showing the embryo
Human embryonic development
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Human embryonic development or human embryogenesis is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embry
Embryo
…parts of the body. Neurulation forms the nervous system, and organogenesis is the development of all the various tissues and organs of the body. A newly developing human is typically referred to as an embryo until the ninth week after conception, when it is then referred to as a fetus. In other multicellular organisms…
Eight-cell embryo, at three days
Histogenesis of the three germ layers
Embryo attached to placenta in amniotic cavity
Nine-week-old human embryo from an ectopic pregnancy