The 'Red Data Book" records:

Options

A. Species diversity of wet lands
B. List of water pollutants
C. List of threatends species
D. Rate of population decline.

Answer

**Step-by-Step Solution:**

1. **Understanding the Red Data Book**: The Red Data Book is a comprehensive public document that serves to record information about species that are at risk of extinction. It is maintained by the International Union for Conservation of Nature (IUCN).

2. **Identifying the Purpose**: The primary purpose of the Red Data Book is to provide information on the conservation status of various species, including plants, animals, and fungi. This includes those that are endangered, vulnerable, or critically endangered.

3. **Evaluating the Options**: The question provides four options:
- Species diversities of wetlands
- List of water pollutants
- A list of threatened species
- The rate of population decline

4. **Analyzing Each Option**:
- **Species diversities of wetlands**: This option does not pertain to the Red Data Book's focus on endangered species.
- **List of water pollutants**: This is related to environmental science and pollution, not species conservation.
- **A list of threatened species**: This aligns perfectly with the purpose of the Red Data Book, which is to document species that are at risk.
- **The rate of population decline**: While this may be an aspect of studying endangered species, it is not the primary focus of the Red Data Book.

5. **Conclusion**: After evaluating the options, the most accurate answer is that the Red Data Book records a list of threatened species.

**Final Answer**: The Red Data Book records a list of threatened species.

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