15 ч 29 мин, 22 сент 2002 г. - First Trimester: Embryo
Описание:
By week 4 the actual embryo is now forming. Alone with the amnion and yolk sac. The amnion is necessary because it surrounds and protects the embryo. It will later on also have more use. The yolk sac produces blood for the embryo.Добавлено на ленту времени:
Дата:
15 ч 29 мин, 22 сент 2002 г.
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~ 23 г назад