Final answer:
The 1967 referendum in Australia is significant as it changed the constitution to recognize Indigenous Australians and allowed the federal government to make laws for them.
Step-by-step explanation:
The significance of one referendum in which the Australian people have protected or changed the Australian constitution can be illustrated by the 1967 referendum. In this pivotal event, over 90% of Australian voters chose to amend the constitution to include Indigenous Australians in the census and allow the federal government to make laws for Indigenous Australians. This significant change contributed to the progress of civil rights in Australia, demonstrating a strong affirmation of equality and federal government's power to enact laws for the benefit of Indigenous communities.
The power to amend the constitution via referendums is critical because it allows a living document to respond to the nation's evolving needs while ensuring substantive changes are not made lightly. However, these changes require a substantial level of public support to succeed, making referendums an essential part of Australia's democratic process, as well as other countries that employ this mechanism.