This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharyngeal Arches, Subject name: Anatomy
External auditory meatus is derived from which cleft? 
Select and explain. 
A. 1, B. 2, C. 3, D. 4
A: 1
Answer: A: 1 
Explanation: Cleft 1 forms external auditory meatus- surface ectoderm If the pharyngeal clefts are not obliterated by the 2nd pharyngeal arch, they can persist into adulthood as branchial (pharyngeal) cysts.