<prompt> Initial stage of clinical union of bone is equivalent toCallus formation with woven boneWoven bone FormationHaematoma formationCalcification formation only  <response>: The first signs of union are seen in stage of hard callus formation A. Clinical sign:fracture is no more mobile B. Radilogical sign :callus is seen on X ray hard callus is immature woven bone Ref: Maheshwari 9the p 12 