sentence: % ​ R = Mean ​ number ​ of ​ tachyzoites ​ in ​ the ​ control ​ group − Mean ​ number ​ of ​ tachyzoites ​ in ​ the ​ infected ​ group × 100Mean ​ number ​ of ​ tachyzoites ​ in ​ the ​ control ​ group2.2.1.3 Viability test .