<prompt> All are true about Diploic veins EXCEPT:Lined by single layer endothelium suppoed by elastic tissuePresent in Cranial bonesValvelessDevelop by 8th week of IUL  <response>: Diploic veins sta developing in the cranial bones at about 2 years of age and are fully developed at the age of 35 years. These are lined by a single layer endothelium suppoed by elastic tissue and are valveless. 