The method by which endangered plant species are conserved in a botanical garden or in some controlled circumstances-

Options

A. Afforestation
B. In situ conservation
C. Ex situ conservation
D. None of the above

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the method by which endangered plant species are conserved in a botanical garden or controlled circumstances.

2. **Identifying the Options**: The options provided are:
- A) Afforestation
- B) In-situ conservation
- C) Ex-situ conservation
- D) None of the above

3. **Analyzing Each Option**:
- **Afforestation**: This refers to the process of planting trees in an area where there was no previous tree cover. It does not relate to the conservation of endangered species in a botanical garden.
- **In-situ conservation**: This method involves conserving species in their natural habitats. It is not applicable to the conservation of plants in a botanical garden, which is a controlled environment.
- **Ex-situ conservation**: This method involves the preservation of living organisms outside their natural habitat. Botanical gardens are examples of ex-situ conservation as they maintain collections of living plants for research and education.

4. **Choosing the Correct Answer**: Based on the analysis, the correct answer is **C) Ex-situ conservation**, as it directly relates to the conservation of endangered plant species in controlled environments like botanical gardens.

### Final Answer:
The method by which endangered plant species are conserved in a botanical garden or in some controlled circumstances is **Ex-situ conservation**.

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