Deepest algae in sea are :-

Options

A. Red algae
B. Brown Algae
C. Green Algae
D. Golden Algae

Answer

To determine the deepest algae in the sea, we will analyze the characteristics of the different types of algae provided in the options: red algae, brown algae, green algae, and golden algae.

### Step-by-Step Solution:

1. **Understanding Algal Pigments**:
- Red algae contain a pigment called R-phycoerythrin, which allows them to absorb light at shorter wavelengths. This pigment is crucial for their survival in deeper waters where light penetration is limited.

**Hint**: Look for the specific pigments that allow algae to photosynthesize at different depths.

2. **Light Penetration in Water**:
- Sunlight penetrates the ocean in varying degrees, with longer wavelengths (like red light) being absorbed quickly. Shorter wavelengths (like blue and green light) penetrate deeper into the water. Red algae can utilize the shorter wavelengths effectively.

**Hint**: Consider how different wavelengths of light affect photosynthesis in algae.

3. **Characteristics of Red Algae**:
- Red algae are known to thrive in deeper parts of the ocean because they can perform photosynthesis using the limited light available at those depths. This ability makes them unique among the types of algae.

**Hint**: Think about which algae can survive in low-light environments.

4. **Comparison with Other Algae**:
- Brown algae are primarily found in shallow waters and along coastlines. Green algae require abundant light and are typically found in well-lit areas. Golden algae can inhabit both freshwater and marine environments but are not specifically adapted for deep-sea conditions.

**Hint**: Compare the habitat preferences of each type of algae to determine which can survive in deeper waters.

5. **Conclusion**:
- Based on the characteristics and adaptations of the algae discussed, the deepest algae in the sea are **red algae**.

### Final Answer:
The deepest algae in the sea are **red algae**.