Final answer:
Federal tax law is created by Congress, which has the power to levy and collect taxes, a key function of government finance. The IRS is responsible for tax collection, and the federal income tax is the main source of national income.
Step-by-step explanation:
The subject in question pertains to the statutory sources of Federal tax law, which are produced by the legislative branch of the U.S. government. According to Article I, Section 8, of the U.S. Constitution, the legislature has enumerated powers, which include the capacity to levy and collect taxes. This is an integral part of financing government expenditures. The power to levy taxes allows Congress to generate revenue, which in 2020 amounted to $3.42 trillion. This revenue is primarily acquired through federal income taxes from individuals and corporations, as well as payroll taxes to fund social security and federal unemployment and disability benefits. The Internal Revenue Service (IRS) is the regulatory authority empowered by Congress to collect these taxes. Additionally, the power to appropriate federal funds, otherwise known as the 'power of the purse', grants Congress substantial control over the executive branch, as it must seek approval from Congress for all of its funding.