The answer is: Market
In the market model, each indviduals have the chance to predict the type of product that the majority of people need / desire. (which they commonly called as 'market demand').
After knowing the market demand, individuals who want to obtain an economic profit need to develop the products in order to answer the market demand. (products that given to the consumers by the sellers is what usually called as market supply)
The Parkland school massacre is an example of an event where people's vivid memories surrounding the event form flashbulb memories.
They weren't agreeing with things that were said
