What is considered to be the greatest threat to species today and is the main cause of endangerment of species?

Extreme natural events
Lack of genetic variation
Symbiotic relationships
Loss of habitat due to human activities

Loss of habitat due to human activities is considered to be the greatest threat to species today and is the main cause of endangerment of species. This includes deforestation, urban development, pollution, and climate change caused by human activities. These factors lead to loss, fragmentation, and degradation of habitats which ultimately threatens the survival of many species.