The external solution having less concentration as that the of cell sap is called

Options

A. Hypertonic solution
B. Isotonic solution
C. Hypotonic solution
D. Ultratonic solution

Answer

To answer the question "The external solution having less concentration as that of cell sap is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Concentration**:
- Concentration refers to the amount of solute present in a solution relative to the amount of solvent. In biological terms, this often refers to the concentration of solutes in the cell sap compared to the external solution.

2. **Types of Solutions**:
- There are three main types of solutions based on their solute concentrations relative to the cell sap:
- **Hypertonic Solution**: This has a higher concentration of solutes compared to the cell sap. Water moves out of the cell, causing it to shrink.
- **Isotonic Solution**: This has an equal concentration of solutes compared to the cell sap. There is no net movement of water into or out of the cell.
- **Hypotonic Solution**: This has a lower concentration of solutes compared to the cell sap. Water moves into the cell, causing it to swell and potentially burst.

3. **Identifying the Correct Solution**:
- Since the question specifies that the external solution has a "less concentration" than that of the cell sap, we are looking for a solution that is hypotonic.

4. **Conclusion**:
- Therefore, the external solution having less concentration than that of the cell sap is called a **Hypotonic Solution**.

### Final Answer:
The answer is **C. Hypotonic solution**.