Which one of the following is an example of ex-situ conservation?

The correct answer is Zoos and botanical gardens.

Understanding Biodiversity Conservation:
Biodiversity conservation strategies are broadly categorized into two types based on where the conservation takes place: In-situ (on-site) and Ex-situ (off-site) conservation.

1. In-situ (On-site) Conservation:
This method involves protecting species in their natural habitats. The entire ecosystem is protected, which allows the species to live, reproduce, and evolve naturally. Examples include:
- National Parks: Strictly protected areas meant for the betterment of wildlife, where human activities like forestry, grazing, or cultivation are not allowed.
- Wildlife Sanctuaries: Areas where wildlife is protected from hunting or disturbance, though limited human activity may be permitted.
- Protected Areas / Biosphere Reserves: Large tracts of natural habitats set aside to preserve biodiversity.
Since National Parks, Wildlife Sanctuaries, and Protected areas conserve species within their natural environment, they are examples of in-situ conservation.

2. Ex-situ (Off-site) Conservation:
This method involves protecting threatened or endangered species outside their natural habitats. Plants or animals are taken from their wild environments and placed in artificial, human-managed settings where they are cared for and protected. Examples include:
- Zoos (Zoological Parks): Facilities where wild animals are kept for public exhibition, education, and breeding programs.
- Botanical Gardens: Managed sites dedicated to the collection, cultivation, preservation, and display of a wide range of plant species.
- Seed Banks / Gene Banks: Places where genetic material is stored at low temperatures for future use.

Therefore, among the given options, Zoos and botanical gardens represent a classic example of ex-situ conservation because organisms are maintained and protected outside of their natural habitat.