In the flower auction, how does the auction make a profit? Does it charge participation or membership fees or take a percentage of sales?

Do participants have to buy/sell of specific quantity to participate?

What the quality of flowers? Do sellers have to meet any standards?

When looking at monopoly power you mention, are you thinking about the auction house itself? Does it have competition from other flower auctions?

What about the agriculture industry does not fit perfect competition exactly? What about entry barriers, especially for large farms? Is quality necessarily the same across sellers?