Once the egg has become multicellular and positioned its germ layers with ectoderm on the outside, mesoderm in the middle, and endoderm on the inside body axes have to be determined for proper development.[8] A dorsal-ventral axis has to form and major proteins involved are BMP and Wnts. Both proteins are made in the ventral and lateral portions of the developing embryo. BMP2B induces cells to have ventral and lateral fates while factors such as chordin can block BMPs to dorsalize the tissue.