Final answer:
Transnational crimes as recognized by the United Nations include terrorism, migrant smuggling, and theft of cultural artifacts, but not underage drinking, which is not a transnational issue.
Step-by-step explanation:
According to the United Nations, the following are considered transnational crimes: terrorism, migrant smuggling, and theft of cultural artifacts. These crimes involve activities that cross national borders and violate both domestic and international laws. Transnational organized crime groups engage in various illegal activities, including human rights violations, drug trafficking, and corruption. Examples include terrorist organizations that operate internationally and networks that smuggle migrants or steal cultural heritage, undermining global governance and security. Underage drinking, however, is not typically classified as a transnational crime as it does not generally involve cross-border criminal activities or networks.