Respuesta :
Mesoderm. In all bilaterian animals, the mesoderm is one of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and endoderm (inside layer), with the mesoderm as the middle layer between them.Mesoderm - Wikipediahttps://en.wikipedia.org/wiki/Mesoderm
a mesoderm is the middle layer of cells or tissues of an embryo
Animals, including earthworms, insects, and humans has mesoderms
Animals, including earthworms, insects, and humans has mesoderms