What are the characteristics of a perfectly competitive market structure?

Perfect competition is a market structure in which there are a large number of small firms competing very intensely. In this market structure no firm has the power to influence the price or supply of traded goods. The characteristics of this market structure include: a large number of small firms, large number of consumers, no asymmetric information: There is no information a firm knows that another don't, firms are price takers, not makers, products are homogeneous, meaning all firms produce the same goods and there are no barriers to entry and exit.
In this model, firms will maximise profits where MC = MR, making no abnormal profit, just enough to stay in competition in the long run. In the short run, if abnormal profits are made, firms will enter and supply the same product, increasing the market's supply and thus lowering the overall price level as supply shifts to the right, leaving firms with the possibility to only make normal profit. An example of this market structure could be vegetables market, where all shops sell homogeneous products, no shop is large enough to influence market supply or price and firms can leave and enter with ease.