Along any downward sloping straight-line demand curve: Group of answer choices both the price elasticity and slope are constant. both the price elasticity and slope vary. the price elasticity varies, but the slope is constant. the slope varies, but the price elasticity is constant.

the price elasticity varies, but the slope is constant

Explanation:

The demand curve is a curve that shows the relationship between price and quantity demanded. The demand curve is negatively sloped because the higher the price, the lower the quantity demanded. This is in line with the law of demand.

According to the law of demand, the higher the price, the lower the quantity demanded and the lower the price, the higher the quantity demanded.

At the midpoint of the demand curve, demand is usually unit elastic. Above the midpoint of the demand curve, demand is elastic and blow the midpoint, demand is inelastic

Price elasticity of demand measures the responsiveness of quantity demanded to changes in price of the good.

Price elasticity of demand = percentage change in quantity demanded / percentage change in price  

Price elasticity of demand = midpoint change in quantity demanded / midpoint change in price  

If the absolute value of price elasticity is greater than one, it means demand is elastic. Elastic demand means that quantity demanded is sensitive to price changes.  

Demand is inelastic if a small change in price has little or no effect on quantity demanded. The absolute value of elasticity would be less than one

Demand is unit elastic if a small change in price has an equal and proportionate effect on quantity demanded.  

Infinitely elastic demand is perfectly elastic demand. Demand falls to zero when price increases  

Perfectly inelastic demand is demand where there is no change in the quantity demanded regardless of changes in price.