Dr. LaGuardia is a cognitive neuroscientist who is interested in the effect of brain concussions on the ability to recognize faces. He conducts a quasi-experimental study in which he examines football players before and after the regular season, using the Benton Facial Recognition Test (a published, widely used measure of one’s ability to recognize faces) to compare those who received concussions to those who did not. He finds that players who had concussions during the regular season performed worse on the Benton Facial Recognition Test than did players who did not experience concussions. Which of the following makes Dr. LaGuardia’s quasi-experimental study different from a correlational study?
A. He used a validated measure of the dependent variable.
B. He was able to confirm the occurrence of a concussion rather than relying on self-report.
C. He used a naturally occurring comparison group (i. e. players who did not suffer a concussion).
D. He used memebers of a real sports team rather than members of the general population.

What is naturalistic about chopin's two stories, "the story of an hour" and "a pair of silk stockings"? provide textual evidence to support your claim.

It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. in fact, however, simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills—suffices. evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills. which of the following, if true, most seriously weakens the force of the evidence cited? (a) as people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them. (b) many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation. (c) many people are proficient both in social interactions and in solving mathematical problems. (d) the study did not itself collect data but analyzed data bearing on the issue from prior studies. (e) the tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.

Which of the following is a primary reason why countries trade