I believe the answer is: Family structures are changing, but families remain important to American life.
The main reason of the changing structures is the increase in divorce rate, and non-monogamous relationship. In the past, almost all children only have one father and one mother. In recent years, children could have more than 2 parents or even only one (in case of single parenthood)
Because the very purpose for studying is to make children who are unable to solve the math problem to become able.
By denying them the opportunity to learn simply because they are deemed not smart enough will even preventing them further from understanding the math topics.
If Congress stretched their powers too far, it is likely that the Supreme Court would step in after a lawsuit and rule that Congress was acting outside the scope provided for it in the Constitution.
Its becuase people of some countries wanted that each and every person of that country should be equal, as they wanted that each and every person, whether a foreigner or born in that country if wanted to be a citizen of that country, they should be. And especially because in ancient times, the usefulness and strength of woman was not being recognised by people, and many people had the wrong idea that men are superior to women and should always be discriminated...this was also the condition with the unequality on the basis of the ranks of people and the property they owned. the rich people were always supported, the middle class people,were dicriminated little, but weren't recognised even though they were great minds, and the poor people were highly dicriminated. So, many countries adopted democracy.
i hope i helped..