Answer: A primary positive effect of the Columbian Exchange is increased food supply of both the Old World and the New World. Various crops such as wheat, barley, and rye, were introduced by Columbus and his followers.
Explanation:
B at the start of a summary
I believe the correct term to fill in the blank would be rumination. Trey is engaging in a practice of rumination. It is a deep or focused thinking of one that has undergone distress. It is analogous with depression and anxiety. When one is ruminating, he keeps thinking of a certain thought repetitively without thinking of any solutions to that problem.
Benjamin Franklin took a great interest in health-related topics by applying Enlightenment reasoning to his study of various afflictions and came up with some astonishingly accurate hypotheses. Benjamin Franklin insights and productivity was in medicine where he saw the value in vaccination against smallpox and was aware of the placebo effect. He launched the first American medical school and devised a flexible urethral catheter. He also identified lead poisoning as a cause of abdominal pain and peripheral neuropathy. He further accurately described psoriasis well before Robert Willan. These contributions by Benjamin Franklin in healthcare may be said to be significant and satisfactory.