The following are multiple choice questions (with answers) about medical knowledge.   **Question:** The menses are 4 weeks overdue in a 23-year-old sexually active woman, thus she is scheduled for an ultrasound examination. The result is shown in the exhibit. What is the function of the structure marked with the green arrow?   (A) Removal of nitrogenous waste   (B) Embryonic hematopoiesis   (C) Production of amniotic fluid   (D) Gas exchange
['(B) Embryonic hematopoiesis <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Removal of nitrogenous waste \n (B) Embryonic hematopoiesis \n (C) Production of amniotic fluid \n (D) Gas exchange <> possible answers', '  The menses are 4 weeks overdue in a 23-year-old sexually active woman, thus she is scheduled for an ultrasound examination. The result is shown in the exhibit. What is the function of the structure marked with the green arrow? <> context@']