Final answer:
The Frontline States advocated for the end of Apartheid and supported the African National Congress and other liberation movements in the region.
Step-by-step explanation:
The collective of neighboring Southern African states that actively advocated for the end of Apartheid was known as the Frontline States. These states, including Angola, Botswana, Mozambique, Tanzania, Zambia, and Zimbabwe, played a significant role in supporting the anti-apartheid movements such as the African National Congress (ANC) and the South West Africa People's Organization (SWAPO). These nations faced various degrees of political, military, and economic repercussions due to their opposition to apartheid and support for liberation movements.