Answer:
The answer is a: less than one million.
Step-by-step explanation:
Endangered species are species of plants and animals that are at risks of extinction either due to natural or anthropological process. The International Union of Conservation of Nature (IUCN) is the body that has been working on assessing different taxonomic groups for threats and species found to be at risk are published in the red list of threatened species.
As at 2019, over 105,000 species have been assessed for threats out of which more than 28,000 species were identified to to be at risk of going into extinction. That is about 27% of the total number of assessed species.
28,000 is still less than a million. The correct option is a