Thorn of Bougainvillea and tendril of Cucurbita are examples of `:`

Options

A. Vestigial organs
B. retrogressive evolution
C. analogous organs
D. homologous organs

Answer

To answer the question "Thorn of Bougainvillea and tendril of Cucurbita are examples of:", we will analyze the options provided and determine the correct classification of these plant structures step by step.

### Step-by-Step Solution:

1. **Understanding the Structures**:
- The thorn of Bougainvillea is a modified branch that serves the purpose of protection.
- The tendril of Cucurbita (commonly known as squash or pumpkin) is also a modified branch, but it serves the purpose of climbing.

2. **Identifying the Options**:
- **Vestigial Organ**: These are organs that were functional in ancestors but are reduced or non-functional in the current organism. This does not apply to thorns and tendrils.
- **Retrogressive Evolution**: This refers to the loss of features over time. This is not relevant to thorns and tendrils as they are functional adaptations.
- **Analogous Organs**: These are organs that serve similar functions but have different structures and origins. This does not apply here since both structures are derived from the same type of organ (branches).
- **Homologous Organs**: These are organs that have a similar structure and origin but may serve different functions. In this case, both the thorn and tendril are modified branches (axillary branches) and have similar anatomical structures, even though they serve different functions.

3. **Conclusion**:
- Since both the thorn of Bougainvillea and the tendril of Cucurbita are modified branches with a common origin but serve different functions, they are classified as **homologous organs**.

### Final Answer:
Thorn of Bougainvillea and tendril of Cucurbita are examples of **homologous organs**.

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