In the usa not in any particular region
<u>Answer:
</u>
The study carried out by Dr. Xu is a randomized controlled study.
<u>Explanation:</u>
- For the sake of determination of how the results of the students change by doing certain changes to the examination pattern, Dr. Xu devised that the change is considerably evident.
- Dr. Xu provided and intervention in the process of exam in the form of guides which helped the students to score better later. Hence, from the standard of conduct of the study, it can be said to be a randomized controlled study.
The Brazilian wandering spider
Based on the options given, the most likely answer to this query is depression and heart disease are correlated, and the risk of heart disease can be reduced by treating depression.
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