Explanation : Properties of Indifference Curves: Indifference curves drawn for two normal substitute goods have the following four basic properties: ∎ Indifference curves have a negative slope; ∎ Indifference curves are convex to the origin; ∎ Indifference curves do not intersect nor are they tangent to one another; ∎ Upper indifference curves indicate a higher level of satisfaction. These properties of indifference curves, in fact, reveal the consumer’s behaviour, his choices and preferences. They are, therefore, very important in the modern theory of consumer behaviour.