<prompt> True about umbilical cord-Cantains two umbilical veinsCantains one umbilical arteryRight umbilical vein disappearsLength is 25-30 cm.  <response>: Ans. is c i.e., Right umbilical vein disappears Umbilical cordo Umbilical cord develops from connecting stalk, which extends from the caudal end of the embryo to the chorion. Umbilical cord is covered by amniotic epithelium and contains a core of mesenchyme known as whartans jelly.o Contents of umbilical cord are : i Wharton fsjelly, ii Two umbilical arteries, iii One left umbilical vein, iv Remnant of yolk sac, and v Remnant of allanto-enteric diverticulum. Initially 2 umbilical arteries and 2 umbilical veins develop in mesoderm, but right umbilical vein disappears. Left umbilical vein persists along with 2 umbilical arteries.o At full term, the umbilical cord measures 1 -2cm in diameter, and 50-55cm in length and generally attached to the center of fetal surface of placenta. 