Final answer:
The three levels of scrutiny used by courts to determine the constitutionality of a government action are rational basis scrutiny, intermediate scrutiny, and strict scrutiny.
Step-by-step explanation:
The three levels of scrutiny used by courts to determine the constitutionality of a government action are rational basis scrutiny, intermediate scrutiny, and strict scrutiny. Rational basis scrutiny is applied to laws that do not involve suspect classifications or fundamental rights, and the government only needs to show a rational reason for the law. Intermediate scrutiny is used for laws that involve gender or legitimacy classifications, and the government must show that the law serves an important government interest and is substantially related to that interest. Strict scrutiny is applied to laws that involve suspect classifications or fundamental rights, and the government must show a compelling government interest and that the law is narrowly tailored to achieve that interest.