Holdfast, stipe and frond constitutes the plant body in case of

Options

A. Rhodophyceae
B. Chlorophyceae
C. Phaeophyceae
D. All of the above.

Explanation

### Step-by-Step Solution:

1. **Identify the Structures**: The question mentions three specific structures: holdfast, stipe, and frond.

2. **Define Each Structure**:
- **Holdfast**: This is a structure that anchors the algae to a substrate, allowing it to remain attached to surfaces in aquatic environments.
- **Stipe**: This is the stalk-like structure that supports the frond, similar to a stem in higher plants.
- **Frond**: This is the leaf-like structure that contains chlorophyll and is responsible for photosynthesis.

3. **Determine the Group**: The question asks which group of organisms these structures belong to. The structures holdfast, stipe, and frond are characteristic of certain types of algae.

4. **Identify the Correct Algal Group**:
- The video transcript mentions that these structures are characteristic features of **Phaeophyceae**, which are commonly known as brown algae.
- Other groups mentioned (Rhodophyceae and Chlorophyceae) do not possess these specific structures.

5. **Conclusion**: Therefore, the plant body structure comprising holdfast, stipe, and frond is found in **Phaeophyceae** (brown algae).

### Final Answer:
Holdfast, stipe, and frond constitute the plant body in the case of **Phaeophyceae** (brown algae).

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