Dear Student,
Wholesalers act as a major participant as they provide the goods to retailers and retailers can provide goods to consumers. With the wholesalers goods are reached to the retailers and this reduce the distance between the producers and the retailers.
And they cause increase in the price of goods because they increase the channel of distribution and with the increase in every element in the distribution channel, prices of the products increases. As wholesalers also charge their profit and this is also included in the price of the products.
Regards