Question

base your answer to the question on the information below and on your knowledge of biology.
ulcers: mystery solved
stomach ulcers are painful sores that develop in the stomach. doctors once thought that ulcers were caused by stress. in the 1980s, a pair of physicians, barry j. marshall and j. robin warren, questioned the cause of ulcers. they found the bacterium helicobacter pylori in the ulcer tissue of their patients. even though they repeatedly presented their findings to colleagues, they were ignored until marshall performed an astonishing experiment: he drank broth containing the bacteria and made himself sick with an ulcer! he then cured himself by taking an antibiotic.
the results were published in 1985, but it took another 10 years for doctors to regularly use antibiotics to treat ulcers. marshall and warren received a nobel prize in 2005 for this discovery.
the work of marshall and warren shows that
○ hypotheses made by physicians are always correct
○ scientific explanations are revised based on new evidence
○ peer review always leads to the immediate acceptance of results
○ conclusions must always be consistent with those made by other scientists

Explanation:

The text shows that initially doctors thought ulcers were caused by stress. But Marshall and Warren's discovery of Helicobacter pylori as the cause (with Marshall's experiment) and the eventual acceptance (after some delay) of using antibiotics (based on this new evidence) to treat ulcers. This indicates that scientific explanations (about the cause of ulcers) were revised when new evidence (the bacteria) came to light.

Answer:

scientific explanations are revised based on new evidence