How did the 1918 flu end?

By the summer of 1919, the flu pandemic came to an end, as those that were infected either die d or developed immunity. Almost 90 years later, in 2008, researchers announced they’d discovered what made the 1918 flu so dea d ly: A group of three genes enabled the virus to weaken a victim’s bronchial tubes and lungs and clear the way for bacterial pneumonia. Since 1918, there have been several other influenza pandemics, although none as de adly. A flu pandemic from 1957 to 1958 k illed around 2 million people worldwide, including some 70,000 people  in the United States, and a pandemic from 1968 to 1969 kill ed approximately 1 million people, including some 34,000 Americans. More than 12,000 Americans perished during the H1N1 (or “swine flu”) pandemic that occurred from 2009 to 2010.

yes ap politics. what do you need?

when studying cause and effect, historians usually group the causes into different categories. for example, cultural causes reflect how a society’s literature and art convey the way the society saw itself in relation to the rest of the world. another resource that historians use to understand society is pop culture, which tells them the trends and ideas that are preferred by the common people. when studying cause and effect, it’s important to remember multiple causation, or the idea that an effect could have several causes and vice versa.  

the correct option is “cultural causes” since art and literature are related to the culture of a place. culture is determined by literature, art, music.

the correct option is “pop culture” since it reflects the likes and ideas of common people whereas the rest of the options do not focus on common people.  

the correct option is “multiple causation” since it refers to the idea that events are caused by multiple reasons, not just a single one.