Thick layers of keratin reduce water loss. Animal is less dependent on moist environment ... Other extra-embryonic folds expand up over the embryo to form the amniotic folds. The amnion and chorion ...

Thick layers of keratin reduce water loss. Animal is less dependent on moist environment ... Other extra-embryonic folds expand up over the embryo to form the amniotic folds. The amnion and chorion ...

The outer membrane (chorion) and trophoblast layer of the placenta are derived from the trophoectoderm of the blastocyst cells. Other extra-embryonic tissues, including the amnion (inner membrane ...