<prompt> Null cells constitute what percentage of peripheral lymphocytes?0-15-Feb10-May15-20  <response>: Ans. c 5-10Ref: Robbins 9thpg 192; 8thpg 188Natural Killer Cells or Null cells constitute 5 to 10 of peripheral lymphocytes QAs NK cells neither have B nor T-cell markers, hence also called Null CellsNK cells destroy irreversibly stressed, virus-infected cells tumor cells without prior exposure 