A clinical scientist investigated the renal function of two individuals on different dietary regimes and health states:
The table below shows the concentrations of glucose, sodium ions, and urea in the urine of both individuals.
| Substance | Concentration in urine of Subject A / g dm−3\text{g dm}^{-3}g dm−3 | Concentration in urine of Subject B / g dm−3\text{g dm}^{-3}g dm−3 |
|---|---|---|
| Glucose | 0.0 | 12.4 |
| Sodium ions | 9.4 | 1.6 |
| Urea | 27.8 | 8.2 |
Evaluate the results shown in the table, explaining the physiological reasons for the differences observed.