Why do writers use in-text citations?

Read this description of a detail from the movie i am legend. a scientist is the last man alive in a post-apocalyptic new york, where zombies have taken over and destroyed most of the population. about ten minutes into the film, the man thinks back to how the zombie creatures came to be, and how at one point he had a wife and child. which type of suspense technique did the screenwriter use? dramatic irony flashback foreshadowing special effects

In saying that 11: 30 am was in the small hours of the morning, bertie is using

The associated press is a wire service in of news around the world. 1.portable 2.importer 3.reporter 4.transport which will fill in the blank need plz