<prompt> Thromboxane A2 causesVasodilatation and platelet aggregaionVasodilatation and anti platelet aggregatoryVasoconstriction and anti platelet aggregatoryVasoconstriction and platelet aggregaion  <response>: Thromboxane A2 secreted by platelets promotes platelet aggregation and vasoconstriction Ref: Ganongs Review of Medical Physiology Twenty-Third Edition Page No:563 