Influenza, commonly known as “flu,” is a highly contagious viral disease that is characterized by fever, respiratory symptoms, fatigue, and muscle pain. The word influenza stems from the Latin root influentia, meaning “influence of the stars,” because before people knew that organisms cause disease, they thought that the stars influenced the spread of influenza. Between 1918 and 1919, how many people were killed in a worldwide lethal flu pandemic? Discuss