Final answer:
The major responsibilities on First Nations reserves fall under the jurisdiction of the federal government, as recognized in the Canadian constitution, with Indigenous chiefs playing a critical role within this framework.
Step-by-step explanation:
The major responsibilities on First Nations reserves primarily fall under the jurisdiction of the federal government. According to the Canadian constitution, which acknowledges the inherent right to self-government by First Nations, the federal government has recognized the obligation to support and protect Indigenous lands, resources, and the administration of laws affecting their lives. Although Indigenous chiefs play a critical role in the governance and day-to-day management of their communities, their authority is in relation to the broader framework established by federal policies and treaties. The provincial governments have limited involvement with First Nations reserves except in delegated areas, and municipalities have even less, if any, direct responsibility over these lands.