In hydrarch, which organism constitute pioneer community ?

Options

A. Phytoplanktons
B. Bryophytes
C. Floating plants
D. Submerged plants

Answer

To answer the question "In hydrarch, which organism constitutes the pioneer community?" we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Hydrarch Succession**:
- Hydrarch succession refers to the ecological succession that occurs in aquatic environments. It involves a series of changes in the species composition of a community over time.

2. **Define Pioneer Community**:
- The pioneer community consists of the first organisms that colonize a barren or disturbed area. These organisms are crucial for initiating the process of succession.

3. **Identify the Initial Organisms in Hydrarch Succession**:
- In aquatic environments, the first organisms to establish themselves are typically small, photosynthetic microorganisms.

4. **Recognize the Role of Phytoplankton**:
- In hydrarch succession, phytoplankton are the initial colonizers. They are microscopic organisms that float in water and perform photosynthesis, making them essential for the ecosystem.

5. **List Other Organisms in Succession**:
- After phytoplankton, other organisms such as free-floating angiosperms and submerged plants will follow in the succession process.

6. **Conclude with the Correct Answer**:
- Therefore, the organism that constitutes the pioneer community in hydrarch succession is **phytoplankton**.

### Final Answer:
The pioneer community in hydrarch succession is constituted by **phytoplankton**.

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