Given below are two statements with respect to gastrulation: Statement (I): The cells of epiblast towards the blastocoel contribute in the formation of yolk sac. Statement (II): The cells of epiblast take part in the formation of third germinal layer, the mesoderm. In light of the above statements, choose the most appropriate answer from the options given below.

Step-by-step solution

Statement (I) is incorrect because the cells of the hypoblast (not epiblast) migrate towards the blastocoel and line its inner surface to form the primary yolk sac. Statement (II) is correct because during gastrulation, cells of the epiblast migrate through the primitive streak to form the intraembryonic mesoderm and embryonic endoderm, while the remaining epiblast cells form the ectoderm. Thus, the epiblast is the source of all three germ layers, including the mesoderm. Answer: Statement (I) is incorrect but State