When Mitt Romney ran for President in 2012, Americans learned that his wife, Anne, had a disease called multiple sclerosis (MS) and that she used to ride horses as therapy. She stood on stage with Mitt and appeared healthy, so her story gave the impression that the disease was not disabling and could be managed by exercise. MS affects 400,000 Americans and usually comes on before the age of 30, with periodic episodes of dizziness, blurred vision or limb weakness. Although most people with MS, liku Anne Romney, are without symptoms of their disease, MS can become progressive and unremitting. It is the leading cause of neurologic disability among young people in the U.S. For this reason, it has been called the polio of our times. Unlike polio, however, we don't know its cause. Over the past 150 years, epidemiologists and other scientists have accumulated a lot of information in an attempt to determine MS's cause. Please classify each fact below into evidence for a genetic cause or evidence for an environmental cause of multiple sclerosis. a. It runs in families: while lifetime risk is 1 in a 1,000 for people who have no close relatives with MS, it is 1 in 3 for identical twins whose twin has MS, 1 in 25 for peopl who have a sibling with MS, and 1 in 50 for people who have a parent with MS. b. The incidence of MS appears to be rising rapidly in many countries. c. Migration studies of MS show the risk changes when people move from high to low prevalence regions. d. It strongly favors Caucasians. e. Disease risk varies depending on where you live. Rates generally are higher in countries farther from the equator. For example, the highest rates in the world are found in Scandinavia. In addition, rates are higher in Australia and New Zealand than in countries in the southern hemisphere closer to the equator. f. Women are three times more likely to be stricken by the disease than men