Explain how each of these costs affect or potentially affect profitability.

Accounting-Cost Structures

As we begin to predict the behavior of costs in accounting, it is important to understand the cost structure. The cost structure is often made up of several different types of costs. Not all costs respond to a change in activity in the same way.
In your own words (in a sentence or two for each), explain each of the following six concepts:
Relevant range
Variable costs
Fixed costs
Step costs
Mixed costs
Contribution margin
Also, explain how each of these costs affect or potentially affect profitability.