The second stage of hydrosere is occupied by plants like

Options

A. Salix
B. Vallisneria
C. Azolla
D. Typha

Explanation

To answer the question regarding the second stage of hydrosere, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the term "hydrosere":**
- Hydrosere refers to a type of ecological succession that occurs in aquatic environments, specifically the transformation of a pond or lake into a terrestrial ecosystem over time.

2. **Identify the stages of hydrosere:**
- The hydrosere consists of several stages:
1. Phytoplankton stage
2. Rooted submerged stage
3. Floating stage
4. Reed-swamp stage
5. Meadow stage
6. Woodland stage
7. Forest stage

3. **Determine the second stage:**
- The second stage of hydrosere is specifically the "Rooted Submerged" stage. This is where plants that are rooted underwater thrive.

4. **Identify the plants in the second stage:**
- Common plants found in the "Rooted Submerged" stage include:
- Valisneria
- Hydrilla

5. **Analyze the options provided:**
- The options given in the question are:
- Salix
- Valisneria
- Azolla
- Typha
- Among these, Valisneria is known to be a rooted submerged plant.

6. **Select the correct answer:**
- Since Valisneria is the only plant listed that belongs to the second stage of hydrosere, the correct answer is **Valisneria**.

### Final Answer:
The second stage of hydrosere is occupied by plants like **Valisneria**.