1. The document discusses endangered species and the threats they face from human activity like habitat destruction, pollution, and hunting.
2. Many animal species are endangered like elephants, rhinos, tigers, pandas, and sea mammals due to loss of habitat from development and pollution of oceans. Overhunting also severely threatens species like rhinos, tigers, and lemurs.
3. The extinction of any species could disrupt entire ecosystems since all plants and animals fill important roles. However, protecting endangered species remains a challenge as some human activities continue to threaten wildlife.