Final Answer:
The National Minimum Drinking Age Act set the legal age for buying and possessing alcohol at 21 years old in the United States.
Step-by-step explanation:
The National Minimum Drinking Age Act (NMDAA) was enacted in 1984 as a response to concerns about alcohol-related accidents and fatalities involving young individuals. The legislation mandated that all states raise their minimum legal drinking age to 21 or face a reduction in federal highway funds. As a result, the legal age for purchasing and possessing alcohol became uniform across the United States, superseding the variation that existed among states before the act. This measure aimed to reduce alcohol-related accidents and promote responsible drinking by delaying legal access to alcohol until individuals reached the age of 21.
In summary, the National Minimum Drinking Age Act established 21 as the legal age for buying and possessing alcohol nationwide.