<prompt> All the following are true about diploic vein exceptLined by single Layer of endothelium suppod by elastic tissuePresent in cranial bonesValvelessthin walledDevelop by 8th week of IUL  <response>: D i.e., Develops by 8th week of IUL The skull is unilamellar at bih with out any diploe and diploic veins which sta to develop at around 2 years after bih. 