Mark the odd one (w.r.t. synthetic auxin)

Options

A. IAA
B. NAA
C. 2, 4-D
D. 2, 4, 5-T

Answer

To solve the question "Mark the odd one (w.r.t. synthetic auxin)", we need to identify which of the given options is not a synthetic auxin. The options provided are:

1. IAA
2. NAA
3. 2,4-D
4. 2,4,5-D

### Step-by-Step Solution:

**Step 1: Understand the Types of Auxins**
- Auxins are plant hormones that regulate growth and development.
- They can be categorized into two types: natural auxins and synthetic auxins.

**Step 2: Identify Natural Auxins**
- The most common natural auxin is Indole-3-acetic acid (IAA).
- Other examples include Indole-3-butyric acid (IBA).

**Step 3: Identify Synthetic Auxins**
- Common synthetic auxins include:
- Naphthalene acetic acid (NAA)
- 2,4-Dichlorophenoxyacetic acid (2,4-D)
- 2,4,5-Trichlorophenoxyacetic acid (2,4,5-D)

**Step 4: Analyze Each Option**
- **IAA**: This is a natural auxin.
- **NAA**: This is a synthetic auxin.
- **2,4-D**: This is a synthetic auxin.
- **2,4,5-D**: This is also a synthetic auxin.

**Step 5: Determine the Odd One Out**
- Since IAA is the only natural auxin among the options, it is the odd one out with respect to synthetic auxins.

### Final Answer:
The odd one out with respect to synthetic auxin is **IAA** (Indole-3-acetic acid).

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