4. What are the four practices that are used as part of the Lean Business Model? (2 points) 5. Explain the differences between variable costs and fixed costs. (2 points) 6. Explain what a cost object is and give some examples. (2 points) 7. Explain the difference between direct costs and indirect costs. (2 points) 8. Explain the difference between period costs and product costs. (2 points)