Microeconomics (from Greek prefix mikro- meaning "small" + economics) may be a branch of economics that studies the behaviour of people and firms in making decisions regarding the allocation of scarce resources and therefore the interactions among these individuals and firms. One goal of microeconomics is to research the market mechanisms that establish relative prices among goods and services and allocate limited resources among alternative uses. Microeconomics shows conditions under which free markets cause desirable allocations. It also analyzes market failure, where markets fail to supply efficient results. While microeconomics focuses on firms and individuals, macroeconomics focuses on the sum of economic activity, handling the problems of growth, inflation, and unemployment and with national policies concerning these issues. Microeconomics also deals with the consequences of economic policies (such as changing taxation levels) on microeconomic behavior and thus on the aforementioned aspects of the economy. Particularly within the wake of the Lucas critique, much of recent macroeconomic theories has been built upon microfoundations i.e. based upon basic assumptions about micro-level behavior.