Acontrolled experiment is designed to test whether h. pylori can survive in acidic conditions that are similar to those found in the stomach. a result showing that h pylori cannot survive in that environment would a) completely eliminate the chances that ulcers are caused by bacteria. b) damage the credibility of the theory that h. pylori are the cause of peptic ulcers. c) lend credibility to the theory that ulcers are caused by stress and other physical factors. d) lend credibility to the theory that ulcers are caused by some form of bacteria, albeit not h. pylori.