This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjunctiva, Subject name: Ophthalmology
Pterygium is- 
Select and explain. 
A. A vascular anomaly, B. A connective tissue degeneration, C. An inflammatory condition, D. Associated with Vit. A deficiency
B: A connective tissue degeneration
Answer: B: A connective tissue degeneration 
Explanation: Pathologically pterygium is a degenerative and hyperplastic condition of conjunctiva. The subconjunctival tissue undergoes elastotic degeneration and proliferates as vascularised granulation tissue under the epithelium, which ultimately encroaches the cornea. The corneal epithelium, Bowman's layer and superficial stroma are destroyed. ref: A K KHURANA OPHTALMOLOGY,E4, Page-80