The demand curve is inelastic for inferior goods and elastic for normal goods.

Elasticity

A measure of how much the quantity demanded or supplied of a good responds to a change in one of its determinants, such as price.

Inferior Goods

Goods for which demand decreases as the income of the consumer increases, opposite to normal goods.

Normal Goods

Goods for which demand increases as the income of consumers increases, and vice versa, holding all other factors constant.