What type of terrorism describes the unlawful use of force or violence by a group whose activities transcend national boundaries?

Answer 1

since their activities cross national boundaries, that would make it international terrorism

Answer 2

The type of terrorism that describes the unlawful use of force or violence by a group whose activities transcend national boundaries is called transnational terrorism. It involves acts of violence and terror that are planned, executed, or supported by individuals or organizations operating across different countries. Transnational terrorist groups often aim to achieve political, ideological, or religious objectives and pose a significant challenge to national and international security.