Once you complete one challenge, you are forced out of the game and must restart it for subsequent challenges. (nintendoworldreport.com)
Even if toxic metals do not come out with an initial urine challenge, they still might be present in storage and could appear in subsequent challenge tests. (drjonathancollin.com)
Results of subsequent challenge studies with these cats supported the earlier predictions of protection made on the basis of antibody titers. (canine-epilepsy-guardian-angels.com)