A. mesoderm layer
B. ectoderm, mesoderm, endoderm
C. ectoderm
D. endoderm
✅ The correct answer is option B.
Germ layer, any of three primary cell layers, formed in the earliest stages of embryonic development, consisting of the endoderm (inner layer), the ectoderm (outer layer), and the mesoderm (middle layer).
Germ layer, any of three primary cell layers, formed in the earliest stages of embryonic development, consisting of the endoderm (inner layer), the ectoderm (outer layer), and the mesoderm (middle layer).