1. Price elasticity of demand measures how responsive the quantity demanded of a good is to changes in its price. It is calculated as the percentage change in quantity demanded divided by the percentage change in price.
2. There are many factors that determine the price elasticity of a good, including whether it is a necessity, if there are substitutes, how many uses it has, and income levels.
3. The degree of elasticity can be perfectly elastic, perfectly inelastic, unitary elastic, relatively elastic, or relatively inelastic depending on how quantity demanded responds to price changes.