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 of marking the odd one with respect to synthetic auxin, we can follow these steps:

### Step 1: Understand the Types of Auxins
Auxins are plant hormones that regulate various aspects of plant growth and development. They can be classified into two main categories: natural auxins and synthetic auxins.

### Step 2: Identify the Options
The options given in the question are:
1. IAA (Indole-3-acetic acid)
2. NAA (Naphthalene acetic acid)
3. 2,4-D (2,4-dichloro-phenoxyacetic acid)
4. 2,4,5-T (2,4,5-trichloro-phenoxyacetic acid)

### Step 3: Classify 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-T**: This is also a synthetic auxin.

### Step 4: Identify the Odd One Out
From the classification:
- IAA is the only natural auxin among the options.
- NAA, 2,4-D, and 2,4,5-T are all synthetic auxins.

### Conclusion
The odd one out with respect to synthetic auxin is **IAA (Indole-3-acetic acid)**, as it is the only natural auxin listed.

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