Step-by-step explanation:
1. A law passed in a state requires all public school students to attend a mandatory Christian prayer session once a week.
This most likely violates both the free exercise clause and the establishment clause. The free exercise clause protects an individual's right to worship or not worship as they please, while the establishment clause prohibits the government from establishing or promoting any one particular religion.
2. A state law requiring all police officers to wear body cameras.
This does not likely violate either the free exercise clause or the establishment clause.
3. A city ordinance that forbids the sale of alcohol on Sundays.
This does not likely violate either the free exercise clause or the establishment clause.