>The changes in the source of raw material >variations in the efficiency of capital and labor >the introduction of new products >the swings of popular fancy from one product to another material variations in the supply of some goods because of weather conditions. and the likeØThe changes in the source of raw material, Øvariations in the efficiency of capital and labor, Øthe introduction of new products, Øthe swings of popular fancy from one product to another, Ømaterial variations in the supply of some goods because of weather conditions, and the like