Question

multiple choice question
the coelom is a fluid - filled cavity that forms completely within the ______ during embryonic development of some bilaterally symmetrical animals.
o endoderm
o ectoderm
o mesoderm

Explanation:

During embryonic development, the coelom (a fluid - filled cavity) forms within the mesoderm. The endoderm forms the inner lining of organs like the digestive tract. The ectoderm forms the outer layer such as the skin and nervous system. The mesoderm is the middle germ layer from which structures like muscles, bones, and the coelom develop.

Answer:

mesoderm