Cellular and Molecular Biology

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Germinal Embryonic Layers


Multicellular organisms usually develop with 2 or 3 germinal layers.

Embryos that develop from two germinal layers are said to be

while those having three germinal layers are termed


The latter group possesses the following germinal layers during development: the ectoderm, mesoderm and endoderm.

In an organism with only two germinal layers, the layers are the


An example of an organism with only two germinal layers is the