What was the negative effect of the columbian exchange on the americas? the trade of crops such as sweet potatoes, peanuts, and maize (corn) with england brought little money. the introduction of unfamiliar livestock such as pigs, horses, sheep, and cows harmed the llama’s environment. the crops from the eastern hemisphere did not grow as well in the western hemisphere. the introduction of diseases for which the native americans had no immunity killed thousands.

The correct answer is D) The introduction of diseases for which the Native Americans had no immunity killed thousands.

The negative effect of the Columbian Exchange on the Americas was the introduction of diseases for which the Native Americans had no immunity killed thousands.

The Columbian exchange had many trade advantages. But among its serious disadvantages was that Europeans introduced many diseases unknown for the Native American Tribes. American Indians were healthy and clean people. They took care of themselves and hygiene was important. But when the Europeans arrived, they introduced diseases such as smallpox, measles, chickenpox, Typhus fever, and influenza. These diseases wiped out entire populations.

roosevelt, a progressive reformer, earned a reputation as a "trust buster" through his regulatory reforms and anti-trust prosecutions. his "square deal" included regulation of railroad rates and pure foods and drugs; he saw it as a fair deal for both the average citizen and the businessmen.