This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Lens develops from: September 2012 
Select and explain. 
A. Neural crest, B. Mesoderm, C. Neuroectoderm, D. Surface ectoderm
D: Surface ectoderm
Answer: D: Surface ectoderm 
Explanation: Ans. D i.e. Surface ectoderm Embryology of eyeball Structures derived from mesoderm: Corneal stroma & endothelium, Only smooth muscles of iris, All muscles (EXCEPT iris muscle) Structures derived from surface ectoderm: Conjunctival epithelium, Lens Structures derived from neuroectoderm: Epithelium of iris & ciliary body, Muscles of iris (constrictor & dilator pupillae)