<prompt> Serotonin, a mediator of inflammation in our body, is secreted released by:LeukocytesEndothelial cellMast cellPlatelet  <response>: Answer- D. PlateletSerotonin :It is found in the intestinal mucosa, brain tissue platelets.Release of serotonin and histamine from platelets is stimulated when platelets aggregate after contact with collagen, thrombin, adenosine diphosphate ADP, and antigen-antibody complexes. 