The goods or services of an individual manufacturer looks the same. It can be substituted completely — that is, if a seller selling goods at a price that is higher than the market price. Consumers will not buy the goods from the vendor.
Each manufacturer of a product or service look identical. It can completely replace it, that is if merchants selling goods at a higher price than the market price. Consumers will not buy from sellers that.
The products or services of producer look exactly alike. It can be replaced completely, that is, if any vendors sell goods at a price higher than the market price. Consumers will not buy the goods from the seller's income.