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: Dental
Tooth develops from: (Or) Calcified structures of
oral cavity develops from 
Select and explain. 
A. Ectoderm, mesoderm, B. Ectoderm, C. Mesoderm, D. Ectoderm and endoderm
A: Ectoderm, mesoderm
Answer: A: Ectoderm, mesoderm 
Explanation: Most of skeletal and connective tissues with exception of enamel are derived from ectomesenchymal tissue. Enamel is derived from ectoderm only. Posterior part of oral cavity is formed from endoderm.