Functions of auxins include

Options

A. promoting flowering in pineapple
B. induing parthenocarpy in tomato
C. use as herbicides to kill dicot weeds
D. all of these

Explanation

### Step-by-Step Solution:

1. **Understanding Auxins**: Auxins are a class of plant hormones that play a crucial role in various growth and developmental processes in plants. They are primarily produced in the tips of stems and roots.

2. **Inducing Flowering**: Certain auxins, such as NAA (Naphthalene acetic acid) and 2,4-D (2,4-Dichlorophenoxyacetic acid), are known to induce flowering in specific plants like pineapple and lychee. This is one of the key functions of auxins.

3. **Parthenocarpy**: Auxins like IAA (Indole-3-acetic acid), IBA (Indole-3-butyric acid), and IBA-alanine are used to induce parthenocarpy, which is the development of fruit without fertilization. When these auxins are applied to un-pollinated pistils, they can stimulate the formation of seedless fruits.

4. **Herbicide Function**: Some auxins, particularly 2,4-D and 2,4,5-T, are utilized as herbicides. They are effective in controlling unwanted plants, specifically dicot weeds, by disrupting their growth processes.

5. **Conclusion**: Based on the functions discussed, auxins have multiple roles including promoting flowering, inducing parthenocarpy, and acting as herbicides. Therefore, the correct answer to the question regarding the functions of auxins is "all of these."

### Final Answer:
The functions of auxins include:
- Promoting flowering in pineapple.
- Inducing parthenocarpy in tomato.
- Being used as herbicides to kill dicot weeds.
Thus, the correct option is **D: all of these**.

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