The mesoderm is the layer that lies between the endoderm and the ectoderm.
Mesoderm forms the middle layer of vertebrate embryos.
Mesoderm is a germ layer that arises during gastrulation.
Gastrulation is the process that establishes all three layers of the ectoderm. endoderm and mesoderm of the embryo.
It is responsible for the formation of notochord, bone, muscles, connective tissues, and circulatory systems, excretory and reproductive systems except for germ cells.