Delayed separation of this structure is often observed in individuals affected by leukocyte adhesion deficiency type 1. Incorrect velamentous (“vill-luh-MEN-tuss”) insertion of either an accessory lobe or this structure usually leads to a condition known as vasa praevia (“vah-sah PREH-vee-ah”). This structure’s blood vessels are surrounded by a proteoglycan-rich substance called Wharton’s jelly. Two arteries and one vein found in this structure are responsible for delivering and draining blood to and from the (*) chorionic (-5[1])villi (-5[1])(“KOR-ree-on-nick VIHL-eye”), respectively. After one procedure, this non-bone marrow structure is clamped and cut from an infant, and its blood can be stored in “banks” for hematopoietic (10[1])(“HEE-mah-toe-POE-eh-tick”) stem cell harvesting. (10[1])For 10 points, name this tube that connects a fetus to the placenta during gestation, whose removal results in the formation of the belly button. (10[1])■END■ (10[1])