Which one of the following statements is wrong?

Options

A. Agar-agar is obtained from Gelidium and Gracilaria
B. Laminaria and Sargassum are used as food
C. Algae increase the level of dissolved oxygen in the immediate environment
D. Algin is obtained from red algae, and carrasteen from brown algae.

Answer

To determine which statement is wrong among the given options, we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Evaluate Statement 1**:
- **Statement**: Agar-agar is obtained from Gelidium and Gracilaria.
- **Analysis**: Agar-agar is indeed derived from these two genera of red algae. This statement is **correct**.

2. **Evaluate Statement 2**:
- **Statement**: Laminaria and Sargassum are used as food.
- **Analysis**: Laminaria and Sargassum are both types of brown algae and are commonly used as food. This statement is **correct**.

3. **Evaluate Statement 3**:
- **Statement**: Algae increase the level of dissolved oxygen in the immediate environment.
- **Analysis**: Algae are photosynthetic organisms that release oxygen as a byproduct of photosynthesis, thus increasing the level of dissolved oxygen in their environment. This statement is **correct**.

4. **Evaluate Statement 4**:
- **Statement**: Algin is obtained from Red Algae and Carrageen is obtained from Brown Algae.
- **Analysis**: This statement is incorrect. Algin is actually obtained from brown algae, while carrageenan is derived from red algae. Therefore, this statement is **wrong**.

### Conclusion:
The wrong statement among the options is **Statement 4**.