Final answer:
The defining characteristic of Canada's territories is that they are under a constitutional monarchy. While the British monarch is a symbolic head of state, the territories have some self-governing powers, but are not fully self-governing like the provinces.
Step-by-step explanation:
Among the options provided, the statement that describes a defining characteristic of Canada's territories is that Canadian territories are under a constitutional monarchy. In a constitutional monarchy, the monarch acts as a ceremonial figurehead, and the real political power lies in elected officials. Canada is a constitutional monarchy and a part of the Commonwealth, with the British monarch as a symbolic head of state while the actual governance is conducted by Canadian officials, including a prime minister and territorial governments. While Canadian territories do have some self-governing powers, they are not fully self-governing in the same way as provinces. The monarch of the United Kingdom does not directly rule the Canadian territories. Instead, the representative of the monarch in Canada is the Governor General, while territories have a Commissioner who represents the federal government. Moreover, no territories in Canada have seceded from the national government.