Final answer:
The increasing number of auto manufacturers making battery-powered cars in a perfectly competitive market would lead to lower prices for car batteries.
Step-by-step explanation:
In a perfectly competitive market, an increase in the number of auto manufacturers making battery-powered cars would lead to an increase in the supply of car batteries. With more suppliers entering the market, the competition among battery manufacturers would intensify, leading to lower prices for car batteries.
For example, if General Motors, Ford, and Chrysler were the only car manufacturers, the competition and consumer choice would be limited. However, with the entry of other manufacturers like Toyota, Honda, and Nissan, there is greater competition and innovation, leading to better cars.
Similarly, as more auto manufacturers produce battery-powered cars, the competition among battery suppliers will increase, leading to lower prices for car batteries.