What is wholesaling, and what are the types of wholesalers?

"Retailers are firms that sell goods to consumers and to industrial users for their own consumption. Wholesalers are firms that sell finished goods to retailers, manufacturers, and institutions. Wholesalers typically sell finished products to retailers and to other institutions, such as manufacturers, schools, and hospitals. The two main types of wholesalers are merchant wholesalers and agents and brokers. Merchant wholesalers buy from manufacturers and sell to other businesses. Agents and brokers are essentially independents who provide buying and selling services. They receive commissions according to their sales and don’t take title (ownership) of the merchandise."