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 that come 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 involves a series of stages that lead from a body of water to a terrestrial ecosystem.

2. **Identify the Stages of Succession**:
- In hydrosere, the stages typically include:
- Phytoplankton stage
- Reed swamp stage
- Submerged plant stage
- Marsh meadow stage
- Submerged free-floating plant stage
- Scrub stage
- Forest stage

3. **Locate the Reed Swamp Stage**:
- According to the sequence of stages in hydrosere, the reed swamp stage is preceded by the phytoplankton stage and followed by the submerged plant stage.

4. **Determine the Answer**:
- Therefore, the stages that come before and after the reed swamp stage are:
- Before: Phytoplankton stage
- After: Submerged plant stage

5. **Select the Correct Option**:
- Based on the options provided, the correct answer is:
- A) Phytoplankton stage and Submerged stage

### Final Answer:
The stages that come before and after the reed-swamp stage are, respectively, **Phytoplankton stage and Submerged stage**.

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