Final answer:
The solution inside the cell is isotonic to the solution outside the cell.
Step-by-step explanation:
Animal cells are permeable to water and urea but NOT to sucrose. In this case, the concentration of sucrose inside the cell is 10 molecules, while the concentration outside the cell is also 10 molecules. On the other hand, the concentration of urea inside the cell is 10 molecules, while the concentration outside the cell is 20 molecules. Based on these concentrations, we can determine that the solution inside the cell is isotonic to the solution outside the cell.