Final answer:
A taxpayer can file as head of household if they are unmarried or 'considered unmarried', have paid more than half of household expenses, and have a qualifying child or relative. This status provides tax benefits like lower rates and higher deductions. The tax system is progressive, with higher income earning higher tax rates.
Step-by-step explanation:
A taxpayer may file as head of household if they meet certain IRS criteria. To qualify, the individual must be unmarried or 'considered unmarried' at the end of the tax year, have paid more than half the cost of maintaining a home for the year, and have a qualifying child or qualifying relative living with them for more than half the year, among other requirements. This filing status allows for a lower tax rate and higher standard deduction than the single filing status.
The U.S. tax system uses progressive tax brackets, which means as a person's income increases, they pay a higher percentage in taxes. This is evident in the tax schedules provided by the IRS, which show different rates for various levels of taxable income, and different brackets based on the filing status such as single, married filing jointly, or head of household.