This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Embryology 2, Subject name: Anatomy
The lateral mesoderm is divided into two distinct layers by the formation of the 
Select and explain. 
A. Extraembryonic coelom, B. Intraembryonic coelom, C. Cardiogenic region, D. Notochord
B: Intraembryonic coelom
Answer: B: Intraembryonic coelom 
Explanation: The lateral mesoderm is a subdivision of intraembryonic mesoderm and initially is a solid plate of mesoderm. The intraembryonic coelom forms in the middle of the lateral mesoderm, thereby dividing it into the intraembryonic somatic mesoderm and intraembryonic visceral mesoderm.