Answer: quantity demanded; price of the goods
Explanation:
Elasticity measures how much one economic variable responds to changes in another economic variable. The price elasticity of demand measures how responsive quantity demanded is to changes in price.
The price elasticity of demand is equal to the percentage change in quantity demanded divided by the percentage change in price. If the quantity demanded changes more than proportionally when price changes, then the price elasticity of demand is greater than 1 in absolute value, and demand is elastic. If the quantity demanded changes less than proportionally when price changes, then the price elasticity of demand is less than 1 in absolute value, and demand is inelastic. If the quantity demanded changes proportionally when price changes, then the price elasticity of demand is equal to 1 in absolute value, and demand is unit elastic.
Perfectly inelastic demand curves are vertical lines, and perfectly elastic demand curves are horizontal lines. Relatively few products have perfectly elastic or perfectly inelastic demand curves.
In terms of income elasticity of demand, a value greater than one implies that the percentage change in the quantity demanded of the good is greater than the percentage change in income.