3. Over time the supply of a particular good or service tends to (LO5) a become more elastic b) become less elastic c) stay about the same 4. Demand is elastic when (LO1) a) percentage change in price is greater than percentage change in quantity b percentage change in quantity is greater than percentage change in price c) the demand curve is vertical d) price increases raise total revenue 5. A perfectly elastic supply curve is (LO1) a horizontal line b) a vertical line c) neither a horizontal nor a vertical line