Final answer:
The legal alcohol limit for someone under 21 in Alabama is 0.02% BAC, aligned with the National Minimum Drinking Age Act of 1984. The standard BAC limit for those of legal drinking age is 0.08%.
Step-by-step explanation:
In the state of Alabama, the legal alcohol limit for a person under the age of 21 is 0.02% blood alcohol concentration (BAC). This stricter limit for underage individuals is in place due to the National Minimum Drinking Age Act of 1984, which required states to enforce a minimum drinking age of twenty-one. For those of legal drinking age, the standard BAC limit is 0.08%. The law in Alabama enforces these limits rigorously to prevent underage drinking and driving under the influence, which can have serious legal consequences.