Assertion (A): The cells in bacteria and parasitic protozoans remain in inactive stage for long periods.
Reason ( R): The cells possess cell walls around them.

Options

A. Both A and R are true and R is the correct explanation for A.
B. Both A and R are true, but R is not the correct explanation for A.
C. A is true and R is false.
D. A is false and R is true.

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts step by step.

### Step 1: Understand the Assertion
The assertion states that "The cells in bacteria and parasitic protozoans remain in inactive stage for long periods."
- **Explanation**: This is true for certain bacteria and parasitic protozoans. For instance, many bacteria can form spores or enter a dormant state under unfavorable conditions, allowing them to survive until conditions improve. Similarly, parasitic protozoans can form cysts that protect them and allow them to remain inactive until they find a suitable host or environment.

### Step 2: Understand the Reason
The reason states that "The cells possess cell walls around them."
- **Explanation**: While it is true that bacteria have cell walls, the presence of a cell wall does not directly cause the cells to remain inactive. Instead, it is the formation of cysts in protozoans that leads to their inactivity. Cysts are protective structures that allow protozoans to survive in harsh conditions, not the cell wall itself.

### Step 3: Analyze the Relationship
Now, we need to determine if the reason supports the assertion.
- **Conclusion**: The assertion is correct, but the reason provided does not correctly explain why bacteria and parasitic protozoans can remain inactive. The inactivity is primarily due to the formation of cysts in protozoans, not just the presence of a cell wall.

### Final Answer
- **Assertion (A)**: True
- **Reason (R)**: False
- Therefore, the correct answer is that the assertion is true, but the reason is not a valid explanation for the assertion.