Find the odd one out from the options showing certain auxins.

Options

A. Indole acetic acid
B. 2,4-D
C. Indole butyric acid
D. Naphthalene acetic acid

Answer

To solve the question of finding the odd one out from the options showing certain auxins, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- A) Indole Acetic Acid (IAA)
- B) 2,4-Dichlorophenoxyacetic Acid (2,4-D)
- C) Indole Butyric Acid (IBA)
- D) Naphthalene Acetic Acid (NAA)

2. **Analyze Indole Acetic Acid (IAA)**:
- IAA is the most common naturally occurring auxin in plants. It plays a crucial role in growth and development.
- **Conclusion**: IAA is an auxin.

3. **Analyze 2,4-Dichlorophenoxyacetic Acid (2,4-D)**:
- 2,4-D is a synthetic herbicide primarily used for weed control. It is not a naturally occurring auxin and is primarily used to kill weeds.
- **Conclusion**: 2,4-D is not classified as an auxin.

4. **Analyze Indole Butyric Acid (IBA)**:
- IBA is another plant hormone that is part of the auxin family. It is often used in rooting powders to promote root formation.
- **Conclusion**: IBA is an auxin.

5. **Analyze Naphthalene Acetic Acid (NAA)**:
- NAA is a synthetic auxin that is used in various agricultural applications, including promoting root growth and fruit development.
- **Conclusion**: NAA is an auxin.

6. **Determine the Odd One Out**:
- From the analysis, we can see that:
- A) IAA - Auxin
- B) 2,4-D - Not an auxin (herbicide)
- C) IBA - Auxin
- D) NAA - Auxin
- Therefore, the odd one out is **B) 2,4-D**.

### Final Answer:
The odd one out is **B) 2,4-Dichlorophenoxyacetic Acid**.

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