I think the check and balances system work really well in united states. This system prevent the government from becoming too tyrannical because it separate our government into legislative, executive, and judiciary branch. If, one government handles all these three, the government could basically violate the law and directly change the law after that so it wouldn't be considered a crime
The question ask to choose among the following choices that is not a difference between schools in Puerto Rico and schools in Los Estados Unidos. Base on the question, the possible answer would be the last choice that states "Students study both spanish and english". I hope this would help