Discuss the reason for the following, using elasticity of demand as the basis for your answer. Motivate your answer with the aid of examples

2.1 Narrowly defined markets tend to be associated with a more price elastic demand than broadly defined markets

2.1.2 Goods tend to have more price elastic demand over large time horizons.

2.1.3 Necessities tend to have relatively inelastic demands, whereas luxuries have relatively elastic demand.