Indicate Which Substance in the Top Column Undergoes the Process

Essay

Indicate which substance in the top column undergoes the process in the lower column by writing the appropriate letter in the blank.
$\begin{array}{lr}\text {1. Filtered and actively reabsorbed but not secreted }&\text { glucose }\_\_\_\_\\\text {2. Filtered but not reabsorbed or secreted }&\text { urea }\_\_\_\_\\\text {3. Filtered and passively reabsorbed }&H^+\_\_\_\_\\\text {4. Not filtered }&K^+\_\_\_\_\\\text { 5. Filtered and both actively reabsorbed and actively }\\\text { secreted }&\text { inulin }\_\_\_\_\\\text { 6. Filtered and secreted, but not reabsorbed }&\text { plasma protein }\_\_\_\_\\\end{array}$