The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Extra-embryonic mesoderm is derived from:   (A) Epiblast   (B) Primary yolk sac   (C) Secondary yolk sac   (D) Hypoblast
['(B) Primary yolk sac <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Epiblast \n (B) Primary yolk sac \n (C) Secondary yolk sac \n (D) Hypoblast <> possible answers', '  Extra-embryonic mesoderm is derived from: <> context@']