[Solved] Narrowing of atherosclerotic vessels must be about __% before blood flow drops to clinically significant levels. A)25 B)50 C)65 D)80 Federal Income Tax: A tax imposed by the United States federal government on the annual earnings of individuals, corporations, trusts, and other legal entities. Return: The gain or loss on an investment over a specified period, expressed as a percentage of the investment's initial cost. Risk: The potential for losing something of value or the uncertainty regarding the outcome of an investment or decision. Investment Spending: The expenditure on physical assets like buildings, machinery, and equipment which is used to produce goods and services in the future.