In Bougainvillea and Citrus thorns are the modification of …………(i)……..and in cactus spines are a modification of ………..(ii)……….

Options

A. `{:((i),"(ii)"),("Adventitious root","Stem"):}`
B. `{:((i),"(ii)"),("Stem","Leaf"):}`
C. `{:((i),"(ii)"),("Leaf","Stem"):}`
D. `{:((i),"(ii)"),("Stipules","Flower"):}`

Answer

To solve the question regarding the modifications in Bougainvillea, Citrus, and Cactus, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Plants**: We need to focus on two types of plants: Bougainvillea and Citrus for the first part, and Cactus for the second part.

2. **Understand the Modifications**:
- **Bougainvillea and Citrus**: Both of these plants have thorns. Thorns are specialized structures that serve a protective function.
- **Cactus**: Cacti have spines, which also serve a protective function but are adapted to their specific environment.

3. **Determine the Origin of Thorns**:
- In Bougainvillea and Citrus, the thorns are actually modifications of the **stem**. This means that the thorns arise from the stem structure of the plant.

4. **Determine the Origin of Spines**:
- In Cactus, the spines are modifications of the **leaf**. In cacti, leaves are reduced to spines to minimize water loss and provide protection.

5. **Compile the Answers**:
- For the first blank (i), the answer is **stem**.
- For the second blank (ii), the answer is **leaf**.

### Final Answer:
In Bougainvillea and Citrus, thorns are the modification of **stem** (i), and in Cactus, spines are a modification of **leaf** (ii).

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