Here are some critical deciding factors for endangered species:1. Population Reduction Rate: An endangered plant or animal is considered when the population declines between 50% to 70%. This decline is measured for ten years or three generations of the species.2. Geographic Range: An endangered animal or plant occurrence extent is less than 5,000 square Km. Their occupancy area is lower than 500 square Km.3. Population Size: Any species gets endangered when there are less than 2,500 mature individuals. When a species' population declines by at least 20% in 5 years or two of their generation, it’s also considered endangered.4. Population Restrictions: A species is classified as endangered when its population restricts to lower than 250 mature individuals. When a species has this lower population, its occupancy area is not considered.5. Extinction Probability: This rate in the wild is at least 20% within 20 years or five generations of the species.