Optic cup is surrounded by -

Ans. is 'd' i.e.Neuroectoderm Formation of optic cupo An outgrowth from prosencephalon forms optic vesicle (neuroectodermal structure)o Proximal part of optic vesicle becomes constricted and elongated to form optic stalko Growing optic vesicle comes in contact with surface ectoderm which is thickened to form lens placodeo Lens vesicle sinks below the surface to form lens vesicle, which is separated from ectoderm and invaginates into optic vesicle to form a double-layered optic cup.Formation of lens vesicle and optic cupChanges in the associated mesodermo During the development of optic vesicle and optic cup, there are developmental changes in mesoderm alsoo The mesoderm surrounding the neural tube gives an extension to cover optic vesicle.o Later, this mesoderm differentiates to form a superficial fibrous layer (which forms cornea and sclera) and deeper vascular layer (which forms Iris, choroid and ciliary body)o With the formation of the optic cup, part of the inner vascular layer of mesoderm is carried into the cup which forms a hyaloid system of vessels.