<prompt> Endothelium activation refers to -Aberration of anatomy of vessel wallIrreversible changes in functional state of vessel wallSmooth muscle proliferationIncreased expression of adhesion molecules for leukocyte recruitment  <response>: Ans. is d i.e., Increased expression of adhesion molecules for leukocyte recruitment o Vascular endothelium in its normal, unactivated state does not bind circulating cells or impede their passage,o In acute inflammation, the endothelium is activated and can bind leukocytes as a prelude to their exit from the bloodvessels.o Inflammatory mediators like thrombin, IL - 1, Platelet Activating Factor, Histamine And TNFactivate endothelial cells by increasing expression of adhesion molecules which can bind leukocytes for leukocyte recruitment. 