In hydrosere, the stages that come before and after the reed-swamp stage are, respectively,

Options

A. Phytoplankton stage and submerged stage
B. submerged stage and submerged free-floating stage
C. submerged free-floating plant stage and marsh-meadow stage
D. submerged free-floating plant stage and scrub stage

Answer

To solve the question regarding the stages before and after the reed-swamp stage in a hydrosere, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Hydrosere**:
- A hydrosere is a type of ecological succession that occurs in aquatic environments. It describes the gradual transition from an aquatic habitat to a terrestrial habitat.

2. **Identify the Stages of Hydrosere**:
- The stages of a hydrosere typically include:
1. **Phytoplankton Stage**: The initial stage dominated by microscopic plants.
2. **Submerged Stage**: Characterized by submerged aquatic plants.
3. **Floating Stage**: Involves plants that float on the water surface.
4. **Reed Swamp Stage**: Dominated by reed plants, indicating a transition to a more terrestrial environment.
5. **Scrub Stage**: The final stage with shrubs and small trees.

3. **Determine the Stages Before and After Reed Swamp**:
- The stage that comes **before** the reed-swamp stage is the **floating stage**.
- The stage that comes **after** the reed-swamp stage is the **scrub stage**.

4. **Select the Correct Option**:
- Based on the identified stages, the correct answer to the question is:
- **Submerged free-floating plant stage** (before reed-swamp) and **scrub stage** (after reed-swamp).

### Final Answer:
The stages that come before and after the reed-swamp stage are, respectively, **submerged free-floating plant stage and scrub stage**.

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