"Yes, divorce is legally acceptable in Australia. The husband or wife may apply for a divorce to the courts, even if the other spouse wishes to continue the marriage."
Australian Citizenship Test gives you access to many more tests than just the one practice test available on the government website. That official sample test is good for giving you an idea of what to expect on the real test. But it can't help you prepare fully. Nor does reading the Australian Citizenship: Our Bond material alone.