Which item is an example of a secondary source

An advantage of primary over secondary sources for any historian would be that they reveal how individuals experienced certain historical events as they were unfolding - this tells us how they actually reacted to the event and not the later revision of their reactions.

the graphs indicate that few people in bolivia work in industry, as that is the least expressive sector shown in the respective graphic.

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.