Which of the following is not obtained from algae ?

Options

A. Mannitol
B. Carrageen
C. Algin
D. Peat

Answer

To determine which of the following is not obtained from algae, let's analyze each option given:

1. **Mannitol**: This is a sugar alcohol that can be found in certain types of brown algae. Therefore, mannitol is obtained from algae.

2. **Carrageen**: This is a gelatinous substance derived from red algae (specifically from the class Rhodophyceae). Hence, carrageen is also obtained from algae.

3. **Algin**: This is a thickening agent that is obtained from brown algae (class Pheophyceae). Thus, algin is obtained from algae as well.

4. **Peat**: This is an accumulation of partially decayed vegetation or organic matter, typically found in wetlands. Peat is primarily derived from mosses, which are classified as bryophytes and not algae.

Based on this analysis, the correct answer is that **peat** is not obtained from algae.

### Step-by-Step Solution:
1. **Identify the substances listed**: Mannitol, carrageen, algin, and peat.
2. **Research the origin of each substance**:
- Mannitol: Found in brown algae.
- Carrageen: Derived from red algae.
- Algin: Obtained from brown algae.
- Peat: Derived from mosses (bryophytes).
3. **Determine which substance is not from algae**: Peat is the only substance that is not obtained from algae.
4. **Conclude the answer**: The correct option is peat.