The initial stages of human embryogenesis.
8-cell embryo, at 3 days.
Blastocyst with an inner cell mass and trophoblast.
Trophoblast differentiation.
Histogenesis of the three germ layers.
Artificially colored - gestational sac, yolk sac and embryo (measuring 3 mm at 5 weeks)
Embryo attached to placenta in amniotic cavity.
Tides are caused by the pull of the moon and position of the earth. High tide is when the moon is further away from the earth and low tide is when the moon is closer to the earth since the water is being pulled in by the moon.
