The supremacy clause, stipulated in article vi of the constitution, holds that
a. in a conflict between federal and state laws, the former will override the latter.
b. in the federal system established by the constitution, the true source of sovereignty is the people.
c. federal laws will be supreme in the national sphere, and state laws will be supreme in local affairs.
d. as a sovereign institution, the state government only needs to obey the limits that it establishes for itself.

A. In a conflict between federal and state laws, the former will override the latter.

Explanation:

The Supremacy Clause establishes that all federal laws are the supreme law of the land and therefore all states, federal officers and judges are bound by it. This means that if a state law is in conflict with federal law, it is the federal law that must prevail: Federal laws override state laws. By describing the relationship between federal and state power, this clause sets the root of the U.S. federalism.

as university of miami psychologists debra lieberman and adam smith pointed out in a recent article in the journal current directions in psychological science, humans have social and psychological mechanisms to deter incest. with very few exceptions, marriages between brothers and sisters and between parents and their children are verboten in every human culture. the primary psychological anti-incest mechanism is the yuck response. even the idea of sex with their mom or dad, bro or sis is upsetting to most people. the psychologist jonathan haidt has found that nearly everyone is repelled by the prospect of brother-sister sex, even in hypothetical situations in which there is no chance of pregnancy).

the biological cost of incest

this raises an interesting question: just what’s so bad about incest? sure, having sex with your dad or your sister seems gross — but why? some anthropologists have argued that incest taboos are learned social conventions. this explanation, however, doesn’t make sense to me as it does not explain the widespread existence of anti-incest mechanisms in creatures ranging from cockroaches to chimpanzees. second, the incest taboo is about as close to a universal law as human moral rules get.

why should mechanisms to avoid incest be so widespread both in nature and across human societies? the answer is simple. the problem with having sex close with relatives is that there is an astonishingly high chance that your offspring will be born with a serious birth defect.