The writer wants to add information to the end of sentence 2 (reproduced below) to preview
the line of reasoning in the passage.
"Unsurprisingly, neuroscientists warn that the constant use of smartphones alters the brain."
Which version of the underlined portion of sentence 2 most effectively accomplishes this
goal?
O brain, the complexities of which have long fascinated psychologists and psychoanalysts
O brain, potentially undermining people's ability to focus on serious school- and work-related tasks
brain, with potentially serious physiological and emotional costs
brain, which may have a profound impact on the still maturing brains of young adults
brain, which many researchers claim may still be evolving
Mi