Biodiversity hotspots are characterized by:
1. High number of endemic species and low threat of extinction
2. Low number of endemic species and low threat of extinction
3. Low number of endemic species and high threat of extinction
4. High number of endemic species and high threat of extinction

A taxon is considered “critically endangered” if it faces a high risk of extinction in the wild in:

The total number of biodiversity hotspots in the world is: