The correct answer is D. threatened species.
A red data book is a document that lists species that are threatened with extinction. It is published by the International Union for Conservation of Nature (IUCN). The IUCN Red List of Threatened Species is the world’s most comprehensive inventory of the global conservation status of biological species. It is used to inform conservation action and policy.
The IUCN Red List is divided into nine categories:
- Extinct in the wild (EW)
- Extinct (EX)
- Critically Endangered (CR)
- Endangered (EN)
- Vulnerable (VU)
- Near Threatened (NT)
- Least Concern (LC)
- Data Deficient (DD)
- Not Evaluated (NE)
Species are assessed against a set of criteria based on their population size, distribution, and threats. The criteria are designed to identify species that are at risk of extinction.
The IUCN Red List is a valuable tool for conservation. It helps to identify species that are at risk and to prioritize conservation efforts. It also helps to raise awareness of the threats facing biodiversity.
Here are brief descriptions of each of the options:
- A. all plant species: The IUCN Red List does not contain data on all plant species. It only includes species that are threatened with extinction.
- B. all animal species: The IUCN Red List does not contain data on all animal species. It only includes species that are threatened with extinction.
- C. economically important species: The IUCN Red List does not contain data on economically important species. It only includes species that are threatened with extinction.
- D. threatened species: The IUCN Red List contains data on threatened species. Threatened species are species that are at risk of extinction.