Final answer:
Simultaneous demand is a product's ability to satisfy a large number of consumers at the same time in a perfect competition market, resulting in increased productivity, lower prices, and more choices for consumers.
Step-by-step explanation:
Simultaneous demand is a product's ability to satisfy a large number of consumers at the same time. In a perfect competition market, there are many sellers offering identical products with no barriers to entry or advantage for existing sellers, resulting in a wide variety of goods and services available to consumers. This leads to increased productivity, lower prices, and more choices for consumers.