Final answer:
The Department of Treasury regulates wines with less than 7% alcohol content through its Alcohol and Tobacco Tax and Trade Bureau.
Step-by-step explanation:
The federal agency that regulates wines with an alcohol content of less than 7% is the Department of Treasury, specifically through its Alcohol and Tobacco Tax and Trade Bureau (TTB). For wines above 7% alcohol by volume, the TTB also regulates labeling, advertising, and ensures that production follows federal regulations. The Food and Drug Administration (FDA) is responsible for regulating nonalcoholic beverages, among other consumer products, but in the case of wine, the FDA's role is more peripheral.