Final answer:
The British Parliament passed the Defence of the Realm Act in order to address the massive war debt and secure the frontier. The Act aimed to raise revenue and allowed for greater control during wartime.
Step-by-step explanation:
The British Parliament passed the Defence of the Realm Act as a response to the massive debt generated by the war and the need to secure the frontier and enforce imperial trade laws. The Act aimed to raise revenue to pay off the debt by requiring everyone, including British subjects in the American colonies, to contribute their share. The Act also allowed for greater control and regulation of activities during wartime, including censorship and restrictions on civil liberties.