URGENT but, What was Australia's contribution to WW1? And why was it impactful?

Australia had an important factor to WW1 that no one really pays attention to:

When the British needed reinforcements, the United States didn’t actually appear in the war for an extended period of time. Australia actually assisted the British in the war against the Germans, though didn’t receive much credit. It was impactful in the sense that the British had additional forces the Germans were not expecting to deal with.

Hope this helps, have a great day!