An indifference curve is a graphical representation of different combinations of two goods that provide equal levels of utility or satisfaction to a consumer. It is a tool used in economics to describe the point where individuals have no particular preference for either one good or another based on their relative quantities. Each point on the curve is a different combination of two goods in various quantities, and theoretically, any point on the curve will provide equal satisfaction (utility) to an individual. The slope of an indifference curve is called the marginal rate of substitution (MRS), and it indicates how much of one good must be sacrificed to keep the utility constant if the other good is increased by one unit. There are infinitely many indifference curves, and a collection of selected indifference curves is referred to as an indifference map. The curve is drawn as a downward sloping convex to the origin, and the graph shows a combination of two goods that the consumer consumes. The indifference curve is used by economists to explain the tradeoffs that people consider when they encounter two goods that they wish to buy. Because people are constrained by a limited budget, they cannot purchase everything, and a cost-benefit analysis must be considered. Indifference curves visually depict this tradeoff by showing which quantities of two goods provide the same utility to a consumer.