Assertion: The color of the leaf is due to the presence of four pigments-chlorophyll a, chlorophyll b, xanthopylls and carotenoids.
Reason: Chlorophyll b is the chief pigment associated with phosynthesis

Explanation

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states: "The color of the leaf is due to the presence of four pigments - chlorophyll a, chlorophyll b, xanthophylls, and carotenoids."

- **Explanation**: This statement is true. The green color of leaves is primarily due to chlorophyll a and b, while xanthophylls (yellow pigments) and carotenoids (orange pigments) contribute to the overall color of the leaf, especially in the fall when chlorophyll breaks down.

### Step 2: Analyze the Reason
The reason states: "Chlorophyll b is the chief pigment associated with photosynthesis."

- **Explanation**: This statement is false. The chief pigment associated with photosynthesis is chlorophyll a. While chlorophyll b plays a supportive role in capturing light energy, it is chlorophyll a that is directly involved in the photosynthetic process.

### Step 3: Conclusion
Based on the analysis:
- The assertion is true.
- The reason is false.

Therefore, the correct answer is that the assertion is true, but the reason is false.

### Final Answer
Assertion is true, but the reason is false.

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