Ex situ conservation is carried out in

Options

A. Sanctuary
B. National Park
C. Biosphere reserve
D. Zoo.

Answer

### Step-by-Step Solution

1. **Understanding Conservation Types**: First, we need to differentiate between the two main types of biodiversity conservation: in-situ and ex-situ conservation. In-situ conservation refers to the conservation of species in their natural habitats, while ex-situ conservation involves the preservation of species outside their natural habitats.

2. **Identifying Ex Situ Conservation**: Ex-situ conservation specifically involves taking plants or animals from their natural environments and placing them in controlled settings. This can include facilities like zoos, botanical gardens, and aquariums.

3. **Examples of Ex Situ Conservation**: The most common examples of ex-situ conservation include:
- **Zoos**: Where animals are kept in captivity for purposes of conservation, education, and research.
- **Botanical Gardens**: Where various plant species are cultivated and preserved outside their natural habitats.

4. **Conclusion**: Based on the definitions and examples discussed, ex-situ conservation is primarily carried out in facilities such as zoos and botanical gardens. Therefore, the answer to the question is that ex-situ conservation is carried out in **zoos**.

### Final Answer
Ex situ conservation is carried out in **zoos**.