Amazon.com, Inc.’s advertising business grew at the slowest pace in five quarters but still delivered a higher growth rate than those of key big-tech rivals Alphabet Inc. and Facebook Inc. as it did a better job facing privacy changes by tech giant Apple Inc. What Happened The e-commerce giant made $8.09 billion from its advertising business in the three months ended Sept. 30, 2021, growing 50 percent year-over-year. Amazon’s advertising revenue in the latest quarter represented about 7.2 percent of its $110.8 billion total revenue. It is gradually turning out to be a key source of growth for the company as momentum in other businesses slows. The Seattle-based tech company does not break out specific financials for advertising, but its “Other” category “primarily includes sales of advertising services, as well as sales related to our other service offerings,” as per the company’s earnings statements. How Do Rivals Stack Up? Amazon’s advertising arm …