Which country uses tax brackets as part of its tax system? canada australia south africa all of the above

All of the above

National Sales Tax and Flat Tax are two major plants that are considered by Congress to fix the tax code. Either of the two will do but they both will do the following:

Both taxes will restore the principle of fairness to the tax system because both will treat all taxpayers equally. 
Both taxes will replace today's discriminatory tax structure with a single low rate.
Both taxes will eliminate the current tax code's bias against savings and investments, and promote a kind of capital formation that will boost workers' incomes and raise long-term economic growth. 
In collecting  said taxes, fewer personnel and paperwork will be needed, resulting to a downsizing of IRS bureaucracy and saving billions of dollars in compliance cost per year. 

Despite their differences, both taxes have the fundamental principle that all income should be taxed at one low rate and only one time, and the collection of tax should be done in the least intrusive way possible.