[A]: Action spectra for photosynthesis help to identify the pigments involved.
[R]: Because these spectron often closely match the absorption spectra of the pig- ments that take part in photosynthesis

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which plants synthesize their own food using sunlight, carbon dioxide, and water. This process occurs primarily in the chloroplasts of plant cells.

2. **Defining Autotrophs**:
- Plants are classified as autotrophs because they can produce their own food through photosynthesis, unlike heterotrophs which rely on other organisms for nutrition.

3. **Introducing Absorption Spectra**:
- The absorption spectra is a graphical representation that shows how much light of different wavelengths is absorbed by pigments involved in photosynthesis. It indicates the efficiency of pigments in absorbing light.

4. **Introducing Action Spectra**:
- The action spectra, on the other hand, illustrates the effectiveness of different wavelengths of light in driving the process of photosynthesis. It shows how the rate of photosynthesis varies with different wavelengths.

5. **Relationship Between Absorption and Action Spectra**:
- Both spectra are related through the wavelengths of light. The absorption spectra indicates which wavelengths are absorbed by the pigments, while the action spectra shows which wavelengths are most effective in promoting photosynthesis.

6. **Conclusion on the Assertion and Reason**:
- The assertion (A) states that action spectra help identify the pigments involved in photosynthesis. The reason (R) explains that this is because the action spectra closely match the absorption spectra of these pigments. Both statements are true and are closely related, as the effectiveness of light in photosynthesis corresponds to the absorption capabilities of the pigments.

### Final Conclusion:
- Both the assertion and reason are true, and the reason correctly explains the assertion.

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