For a solution at atmospheric pressure , `Psi_(W)` is equivalent to

Answer

To solve the question "For a solution at atmospheric pressure, `Ψ_W` is equivalent to:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand Water Potential (Ψ_W)**:
- Water potential (Ψ_W) is a measure of the potential energy in water and is influenced by solute concentration and pressure.
- It is expressed in the formula:
\[ Ψ_W = Ψ_S + Ψ_P \]
where:
- Ψ_S = Solute potential
- Ψ_P = Pressure potential

2. **Consider Atmospheric Pressure**:
- At atmospheric pressure, the pressure potential (Ψ_P) is typically considered to be zero. This is because atmospheric pressure is the reference point for measuring pressure in plants.

3. **Substituting Values**:
- Since Ψ_P = 0 at atmospheric pressure, we can simplify the water potential equation:
\[ Ψ_W = Ψ_S + 0 \]
- Therefore, we have:
\[ Ψ_W = Ψ_S \]

4. **Conclusion**:
- This means that for a solution at atmospheric pressure, the water potential (Ψ_W) is equivalent to the solute potential (Ψ_S).

5. **Final Answer**:
- Thus, the correct answer is:
\[ Ψ_W \text{ is equivalent to } Ψ_S \]