This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
Corneal stroma is derived from 
Select and explain. 
A. Paraxial mesoderm, B. Intermediate mesoderm, C. Neural crest, D. Ectoderm
C: Neural crest
Answer: C: Neural crest 
Explanation: The corneal stroma is a mesenchymal tissue, derived from the periocular neural crest, is the thickest layer of the cornea, and is 'sandwiched' between the epithelium and the inner endothelium. The stroma is composed of organized collagen, mainly type I and type V collagen fibers, which maintain transparency. Keratocytes (fibroblasts) are located between the lamella collagen fibers and secrete an extracellular matrix, which includes collagen and proteoglycans, and also produce crystalline proteins to maintain corneal transparency. Ref - Pubmed.com