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 carrageenan from brown algae.

Answer

To determine which statement is wrong, let's analyze each statement one by one:

1. **Statement 1**: "Agar agar is obtained from Gelidium and Gracilaria."
- **Analysis**: This statement is correct. Both Gelidium and Gracilaria are types of red algae from which agar is extracted.

2. **Statement 2**: "Laminarin and Sargassum are used as food."
- **Analysis**: This statement is also correct. Laminarin is a carbohydrate stored in brown algae, and Sargassum is a genus of brown algae that can be consumed.

3. **Statement 3**: "Algae increases the level of dissolved oxygen in the immediate environment."
- **Analysis**: This statement is correct as well. Algae, through the process of photosynthesis, release oxygen into the water, thus increasing the level of dissolved oxygen.

4. **Statement 4**: "Algin is obtained from Red Algae and Carrageenan is obtained from Brown Algae."
- **Analysis**: This statement is incorrect. Algin is actually obtained from brown algae, while carrageenan is derived from red algae.

**Conclusion**: The wrong statement is the fourth one.

### Step-by-Step Solution:
1. Read and analyze each statement carefully.
2. Verify the sources of agar, algin, and carrageenan.
3. Identify which statement contains incorrect information.
4. Conclude that the fourth statement is wrong.