Answer:
1. Wages of assembly line workers _____Variable ____________
2. President's salary ______Fixed___________
3. Plant utilities _______Mixed__________
4. Sales force commissions _____Variable____________
5. Shipping costs ______Variable___________
6. Factory rent ________Fixed_________
7. Research and development expenses _____* Fixed____________
8. Property taxes _______Fixed__________
9. Advertising _______Fixed__________
10. Supplies used in production _____Variable____________
* If you consider output as number of units sold the R&D is a fixed cost.