Final answer:
The Breivik massacre was primarily driven by extremist ideology, nationalism, and Breivik's personal beliefs, reflecting common motivations for terrorism such as religious extremism, national independence, and racial supremacy.
Step-by-step explanation:
The Breivik massacre seems to have been motivated by a combination of nationalism, extremist ideology, and a personal worldview. This aligns with patterns in past terrorist actions, which have been driven by ideologies such as religious extremism, national independence movements, racial supremacies like White nationalism or neo-Nazism, as well as various forms of extreme nationalism. Motivations for such horrendous acts can stem from a desire to impose a certain worldview on society, whether it's based on religion, a perceived cultural superiority, or in response to political changes affecting the rights of a particular group.