Phytohormone A causes apical dominance while phytohormone B overcomes the same. Select the option that correctly identifies A and B.

Options

A. `{:(A,B),("Auxin","Cytokinin"):}`
B. `{:(A,B),("Cytokinin","Auxin"):}`
C. `{:(A,B),("Gibberellin ","Cytokinin "):}`
D. `{:(A,B),("Auxin","Gibberellin"):}`

Answer

To solve the question regarding which phytohormone causes apical dominance and which one overcomes it, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Apical Dominance**:
- Apical dominance is a phenomenon where the main central stem of the plant grows more strongly than the other side stems. This is primarily due to the presence of certain hormones.

2. **Identify Phytohormone A**:
- Phytohormone A is responsible for promoting apical dominance. The hormone that plays this role is **Auxin**. Auxin is produced at the tip of the plant and encourages the growth of the apical bud, inhibiting the growth of lateral buds.

3. **Identify Phytohormone B**:
- Phytohormone B is responsible for overcoming apical dominance. The hormone that counteracts the effects of auxin and promotes the growth of lateral buds is **Cytokinin**. Cytokinins promote cell division and can stimulate lateral bud growth, thus overcoming the dominance of the apical bud.

4. **Conclusion**:
- Therefore, the correct identification of the phytohormones is:
- Phytohormone A (causes apical dominance) = **Auxin**
- Phytohormone B (overcomes apical dominance) = **Cytokinin**

### Final Answer:
Phytohormone A is Auxin, and Phytohormone B is Cytokinin.

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