Final answer:
Sales, income, and gasoline taxes are examples of government revenue sources, with sales taxes being notably regressive, income taxes applying to personal and corporate earnings, and excise taxes impacting consumers of goods like gasoline.
Step-by-step explanation:
Taxes on retail sales, income, and gasoline are all examples of government revenue sources. Sales taxes are imposed as a percentage of firms' sales on retail transactions, and while they can be regressive, affecting individuals with lower incomes more, they constitute a significant portion of state government revenues, sometimes making up about 47% of total tax revenue. Income taxes, on the other hand, are typically levied on both personal and corporate income, serving as substantial sources of both state and federal revenues. As individuals' income increases, supply-siders argue for a tax system that lowers overall rates, a principle often seen in regressive taxes such as excise or 'sin' taxes on goods like gasoline, which also play a role as a revenue source and can be seen as having a regressive impact due to consumption not rising proportionally with income.