The pigment that absorbs red and far red light in plants is

Options

A. Option1 carotene.
B. Option2 xanthophyll.
C. Option3 chlorophyll.
D. Option4 phytochrome.

Answer

To solve the question regarding which pigment absorbs red and far-red light in plants, we will analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understanding the Question**:
- The question asks for the pigment that specifically absorbs red and far-red light in plants.

2. **Analyzing the Options**:
- **Option A: Keratin**:
- Keratin is not a pigment found in plants; it is a protein that forms the structure of hair, nails, and skin in animals. Therefore, this option can be eliminated.

- **Option B: Xanthophyll**:
- Xanthophyll is a yellow pigment found in plants, primarily responsible for the yellow color in leaves. It does not absorb red or far-red light, so this option is also incorrect.

- **Option C: Chlorophyll**:
- Chlorophyll is the green pigment in plants that is essential for photosynthesis. While it absorbs light, it primarily absorbs blue and red light, but it does not specifically absorb far-red light. Thus, this option is not the correct answer.

- **Option D: Phytochrome**:
- Phytochrome is a photoreceptor pigment in plants that is sensitive to red (around 660 nm) and far-red light (around 730 nm). It exists in two interconvertible forms: Pr (which absorbs red light) and Pfr (which absorbs far-red light). This makes phytochrome the correct answer.

3. **Conclusion**:
- Based on the analysis of each option, the pigment that absorbs red and far-red light in plants is **Phytochrome**.

### Final Answer:
**Phytochrome**