Answer:(a) The International Union for Conservation of Nature (IUCN).
The Invasive Species Specialist Group (ISSG), which develops the Global Invasive Species Database, belongs to (a) The International Union for Conservation of Nature (IUCN).
Explanation:
The Invasive Species Specialist Group (ISSG) is a global network of scientific experts working under the umbrella of the International Union for Conservation of Nature (IUCN). The ISSG is dedicated to addressing the issue of invasive alien species and their impact on biodiversity, ecosystems, and human well-being. One of its key initiatives is the development and maintenance of the Global Invasive Species Database, which provides comprehensive information on invasive species worldwide.
Reference source:
The information about the Invasive Species Specialist Group (ISSG) being a part of the International Union for Conservation of Nature (IUCN) can be found on the official website of the IUCN, which is a reputable and authoritative source. You can refer to the IUCN website for further details:
https://www.iucn.org/theme/species/our-work/invasive-species
Additionally, the information can also be cross-verified through relevant publications and resources on invasive species, conservation, and biodiversity, such as those provided by the United Nations Environment Programme (UNEP) and other reputable international organizations.