Which CITES appendix corresponds to the most endangered species threatened with extinction?

Appendix I of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) is designated for species that are the most endangered and are threatened with extinction. This appendix includes species that are prohibited from international trade unless under exceptional circumstances, such as scientific research or conservation purposes. The strict regulations surrounding Appendix I species are critical for their survival, as they face significant threats from habitat loss, poaching, and illegal trade.

In contrast, Appendix II includes species that are not necessarily threatened with extinction but may become so if trade is not closely controlled. Appendix III contains species that are protected in at least one country, which has requested assistance from CITES in regulating trade. Therefore, the designation of Appendix I specifically highlights the most urgent conservation needs for the most endangered species, making it the correct answer.