In mammals, a tissue formed within the uterus through which nutrients are passed from the mother to the embryo (and later the fetus) and its wastes are removed. It is analogous to ...
In animals with three tissue layers (i.e. all except sponges and cnidarians), the middle layer of tissue, between the ectoderm and the endoderm. In vertebrates, for instance, the ...
Often loosely applied to any movable, toothed structures at or near the mouth of an animal, such as the scolecodonts of annelids. In vertebrates, the jaw is derived from the first ...
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