Which is not a natural plant hormone ?

Options

A. `GA_(3)`
B. `GA_(2)`
C. IAA
D. 2, 4-D

Answer

To determine which is not a natural plant hormone, we can follow these steps:

### Step 1: Identify the given hormones
We are provided with four hormones to analyze: GA3, GA2, IAA, and 2,4-D.

### Step 2: Classify the hormones
- **GA3 and GA2**: Both of these are types of gibberellins, which are natural plant hormones that promote growth and development in plants.
- **IAA**: This stands for indole acetic acid, which is the most common natural auxin. Auxins are also natural plant hormones that play a crucial role in plant growth.
- **2,4-D**: This is known as 2,4-dichlorophenoxyacetic acid, which is a synthetic auxin. It is not naturally occurring in plants and is primarily used as a herbicide.

### Step 3: Determine which hormone is synthetic
From the classifications:
- GA3, GA2, and IAA are all natural plant hormones.
- 2,4-D is a synthetic hormone.

### Conclusion
The hormone that is not a natural plant hormone is **2,4-D**.

### Final Answer
**2,4-D** is not a natural plant hormone.

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