Which one of the following statement is wrong?

Options

A. Algae increases the level of dissolved oxygen in the immediate environment
B. Algin is obtained from red algae and carrageenan from brown algae
C. agar-agar is obtained from gelidium and gracilaria
D. Laminaria and sargassum are used as food

Answer

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

1. **Statement 1**: "Lg increases the level of dissolved oxygen in the immediate environment."
- This statement is true. Lg refers to a group of photosynthetic organisms (likely referring to algae), which perform photosynthesis. During photosynthesis, oxygen is released, thereby increasing the level of dissolved oxygen in the surrounding water.

2. **Statement 2**: "Lg is obtained from red algae and carrageenan from the brown algae."
- This statement is incorrect. Lg (likely referring to algin or a similar substance) is derived from brown algae (Phaeophyta), while carrageenan is obtained from red algae (Rhodophyta). Therefore, this statement misattributes the sources of these substances.

3. **Statement 3**: "Agar agar is obtained from Gelidium and Gracilaria."
- This statement is true. Agar agar is indeed obtained from red algae, specifically from the genera Gelidium and Gracilaria. It is commonly used in laboratories for various applications, including gel electrophoresis.

4. **Statement 4**: "Laminaria and Sargassum are used as food."
- This statement is true. Laminaria and Sargassum are types of brown algae (Phaeophyta) that are cultivated and consumed as food in various cultures.

After analyzing all the statements, it is clear that the wrong statement is **Statement 2**.

### Summary of the Solution:
- Statement 1: True
- Statement 2: **Wrong**
- Statement 3: True
- Statement 4: True

### Final Answer:
The incorrect statement is **Statement 2**: "Lg is obtained from red algae and carrageenan from the brown algae."