A student is studying how the kidneys filter blood. The table below shows the concentrations of two substances in the blood plasma entering the glomerulus and in the filtrate inside the Bowman's capsule.
| Substance | Concentration in blood plasma (g/dm3\text{g/dm}^3g/dm3) | Concentration in filtrate (g/dm3\text{g/dm}^3g/dm3) |
|---|---|---|
| Urea | 0.3 | 0.3 |
| Albumin (a protein) | 42.0 | 0.0 |
Explain the difference in the concentration of albumin in the blood plasma and in the filtrate.