A : Carotenoids protect plant from excessive heat and prevent photoxidation of chlorophyll.
R : Carotenodis enable a wider range of wavelength of incoming light to be utilised for photosynthesis.

Options

A. If both Assertion % Reson ar true and the reason is the correct explanation of the asserition the mark (1)
B. If both Assertion % Reason are true but the reason, is not the correct explanation of the assertion ,then mark (2)
C. If Assetion is true statement but Reason is false , The mark (3)
D. If both Assertion and Reason are false statements, the mark (4)

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Assertion (A)**: The assertion states that "Carotenoids protect plants from excessive heat and prevent photoxidation of chlorophyll." This means that carotenoids play a protective role in plants by absorbing excess light energy that could otherwise damage chlorophyll molecules.

2. **Understanding the Reason (R)**: The reason states that "Carotenoids enable a wider range of wavelengths of incoming light to be utilized for photosynthesis." This indicates that carotenoids can absorb light energy at different wavelengths, which allows for more efficient photosynthesis.

3. **Role of Carotenoids**: Carotenoids are accessory pigments found in the light-harvesting complexes of plants. They absorb light energy and transfer it to the reaction center (chlorophyll A) through a process called resonance energy transfer. This process helps to protect the chlorophyll from excessive light that could lead to photooxidation.

4. **Protection Mechanism**: When excessive light hits the plant, carotenoids absorb some of this energy, which prevents the chlorophyll from being overwhelmed. If carotenoids were not present, the chlorophyll A could be damaged by too much light energy, leading to photoxidation.

5. **Conclusion**: Both the assertion and the reason are true. The reason provides a correct explanation for the assertion, as the ability of carotenoids to absorb a wider range of wavelengths contributes to their protective role against excessive light and heat.

6. **Final Answer**: Since both the assertion and reason are true, and the reason correctly explains the assertion, the answer is that both statements are true and the reason is the correct explanation for the assertion.

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