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?
A. brain, the complexities of which have long fascinated psychologists and psychoanalysts

B. brain, potentially undermining people’s ability to focus on serious school- and work-related tasks

C. brain, with potentially serious physiological and emotional costs

D. brain, which may have a profound impact on the still-maturing brains of young adults

E. brain, which many researchers claim may still be evolving

the answer is C) brain, with potentially serious psychological and emotional costs

Explanation:

This is the correct answer according to collegeboard on AP classroom 2021.

AP classroom explanation : This choice best previews the passages line of reasoning. The second paragraph explains how frequent phone notifications caused the brain to release dopamine, and the third paragraph explains how this change in the release of dopamine cause a psychological and psychological effects, such an elevated pulse, shortness of breath, and higher levels of anxiety

for this case, we must find the number of deaths per day of the year 2015, in automobile accidents, knowing that 32,400 people died.

knowing that the year 2015 had 365 days we have the following division:

where "x" represents the number of deaths per day.

rounding off we have:

approximately, 89 people per day died in 2015

answer:

89 people per day