Choose the term that most appropriately completes the following statements: are costs that can be easily or physically traced to a particular cost object. - Direct material and direct labour are combined to form - is a cost that varies, in total, in direct proportion to changes in the level of activity or volume. - Fixed costs per unit will when the level of activity increases. - Semi-variable costs include an amount that is fixed within a relevant range of output and an amount that varies with output changes