How many zones are present in a Biosphere reserve ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Biosphere Reserves**: A biosphere reserve is a designated area that aims to conserve biodiversity and promote sustainable development. It is an example of in-situ conservation, which means conservation of species in their natural habitats.

2. **Identifying the Zones**: Biosphere reserves are organized into three interrelated zones. Each zone has a specific purpose and level of human activity allowed.

3. **Core Zone**: The innermost zone is called the core zone. This area is strictly protected and is primarily for the conservation of biodiversity. Human activities are highly restricted in this zone to minimize disturbance to the ecosystem.

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