Listed here are product costs for the production of soccer balls. Classify each cost as either direct or indirect.

\begin{tabular}{|l|l|} \hline \multicolumn{1}{|c|}{ Product Cost } & Direct or Indirect \\ \hline 1. Coolants for machinery & \\ \hline 2. Wages of product assembly workers & \\ \hline 3. Annual flat fee paid for factory security & \\ \hline 4. Taxes on factory & \\ \hline 5. Machinery depreciation (straight-line) & \\ \hline 6. Rubber bladder interior for balls & \\ \hline 7. Factory building rent & \\ \hline 8. Wages of factory machine operators & \\ \hline 9. Wages of factory maintenance workers & \\ \hline 10. Factory supervisor salary & \\ \hline \end{tabular}