Scale effect: refers to the effect that the average cost of a product decreases continuously with the increase of production. Due to the relative concentration of the region and the technical aspects of each other, the cost-saving methods also spread and promote each other, thereby forming an external economy of scale. Production costs, information costs, and management cost all continue to decrease with increasing output, which enhances the competitiveness of the product. The scale advantage of the enterprise group also constitutes its cost advantage. Which of the following are scale effects:. ['Due to the increase in the production capacity of the PC industry, the supply of spare parts is sufficient, the demand is growing, and the comprehensive cost continues to decline.', "Facing the competition of many domestic personal auction websites, Taobao decided to adopt a three-year free user experience, which reduced the cost of customers' auction products.", "Wal-Mart's direct procurement model eliminates unnecessary intermediate links and greatly reduces product costs.", 'Most laptop computers now have integrated cameras, which effectively reduces the cost of consumer purchases.']