<prompt> In PT test, the addition of Ca2 tissue thromboplastin activates which pathway?ExtrinsicIntrinsicFibrinolyticCommon  <response>: Ans. a ExtrinsicTo PT we add of Ca2 tissue thromboplastin which activates extrinsic pathway, while to test for aPTT we add kaolin, silica which activates intrinsic pathway. 