What is cost behavior oriented approach.

a. absorption costing

cost behaviour refers to the analysis of total costs as variable and fixed costs. Variable cost remain constant per unit while fixed costs remain constant in total. In absorption costing, variable and fixed manufacturing costs are added to the cost of inventory. The fixed manufacturing costs may be estimated (budgeted as fixed overhead per unit). Marginal costing refers only to the incremental costs, process and job costing apply to different industries. 

Could you please explain Job order costing and Marginal Costing too?