The first reason is their size. They are very small and are very difficult to see. Special technology needed to be developed in order to observe them and their behavior and reach the conclusion that they were in fact infectious agents that could cause diseases. This wasn't possible before because the microscopes weren't as well developed.
Another is that they have a very long incubation period. This means that if you have them, a long time will pass before they start harming you which meant that many people believed them to be harmless since they couldn't track their behavior over a longer time period, also due to the lack of good technology.
Racism and sexism came hand and hand but if anything classism seems like the first where royalty or nobility would look down on people with lower social status like peasants.
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Operation Desert Storm was the first major foreign crisis for the United States after the end of the Cold War. On Aug. 2, 1990, Saddam Hussein led a well-equipped Iraqi army into Kuwait, a major supplier of oil to the United States.
In 1887, Congress established a commission to regulate the railroads by passing "The Interstate Commerce Act", which was mainly intended to keep railroad companies from becoming monopolies.
