Assertion :- The net direction and rate of osmosis depends on both pressure gradient and concentration gradient,
Reason:- Water potential is mainly governed by sum total of pressure potential and osmotic potential

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false

Answer

To analyze the given assertion and reason, we can break down the statements and evaluate their validity step by step.

### Step 1: Understand the Assertion
The assertion states that "The net direction and rate of osmosis depends on both pressure gradient and concentration gradient."

- **Explanation**: Osmosis is the movement of water across a semipermeable membrane from a region of lower solute concentration (higher water potential) to a region of higher solute concentration (lower water potential). The pressure gradient (the difference in pressure across the membrane) and the concentration gradient (the difference in solute concentration) both influence the movement of water.

**Hint**: Consider how pressure and concentration affect the movement of water molecules.

### Step 2: Understand the Reason
The reason states that "Water potential is mainly governed by the sum total of pressure potential and osmotic potential."

- **Explanation**: Water potential (Ψ) is a measure of the potential energy in water and is influenced by two main components: pressure potential (Ψp), which is the physical pressure on a solution, and osmotic potential (Ψs), which is the potential due to solute concentration. The relationship can be expressed as:
\[ Ψ = Ψp + Ψs \]
This means that the overall water potential is determined by both the pressure and osmotic potentials.

**Hint**: Recall the formula for water potential and how each component contributes to it.

### Step 3: Evaluate the Relationship Between Assertion and Reason
Now, we need to determine if the reason correctly explains the assertion.

- The assertion is true because both pressure gradient and concentration gradient affect osmosis.
- The reason is also true because water potential is indeed the sum of pressure potential and osmotic potential.

However, while the reason provides a correct explanation of water potential, it does not directly explain why the direction and rate of osmosis depend on both gradients. The assertion is more about the factors affecting osmosis, while the reason discusses water potential.

**Hint**: Think about whether the reason directly clarifies the assertion or if it simply supports a related concept.

### Conclusion
Given that both the assertion and reason are true, but the reason does not serve as a correct explanation for the assertion, the correct answer is:

**Option 2**: Both assertion and reason are true but reason is not the correct explanation of assertion.