Final answer:
Indirect costs are the costs that cannot be easily attributed to a specific product or service, as opposed to direct costs which can be traced directly. Variable costs change with output levels, while marginal costs increase with each additional unit produced.
Step-by-step explanation:
The costs that are difficult to attribute or allocate to a specific output or work activity are known as indirect costs. Unlike direct costs, which can be directly traced to a product or service, indirect costs are not tied to any one cost object and may include expenses like manufacturing overhead, utilities, and rent. Direct costs, on the other hand, are tied to the production of a specific good or service, such as raw materials and labor. Variable costs are those that vary with the level of output, increasing or decreasing as more or less of a good or service is produced, and include costs for variable inputs like labor and raw materials. Marginal costs refer to the increase in total costs from producing one additional unit of output, and typically rise due to diminishing marginal returns.