Red data book is maintained by
Or
List of endangered species was released by
Or
The organization which publishes the Red List of species is

Options

A. GEF
B. IUCN
C. UNEP
D. WWF

Answer

### Step-by-Step Solution:

1. **Understanding the Red Data Book**: The Red Data Book is a comprehensive document that compiles information about endangered species of plants and animals, including some subspecies. It serves as a public document that anyone can access to learn about the status of various species.

2. **Purpose of the Red Data Book**: The primary purpose of the Red Data Book is to provide detailed information about the research, study, and monitoring programs related to rare and endangered species. This helps in conservation efforts and awareness.

3. **Identifying the Maintaining Organization**: The Red Data Book and the list of endangered species are maintained and published by an organization that specializes in conservation efforts.

4. **Recognizing the Organization**: The organization responsible for maintaining the Red Data Book and publishing the Red List of species is the International Union for Conservation of Nature (IUCN).

5. **Final Answer**: Therefore, the answers to the questions: "Red Data Book is maintained by," "List of endangered species was released by," and "The organization which publishes the Red List of species is," is the IUCN (International Union for Conservation of Nature).