The biological aspects of the Terai region are described as follows:
- This region is favourable for agriculture due to the warm climate, high fertility of soil with humus, inorganic and organic substances.
- In this region diversity of vegetation and animals is very high due to high temperature, fertile land and availability of water.
- The main crops cultivated in this region are rice, wheat, maize, oilseeds, etc.
- The main vegetation in the forests includes sal, sissau, khayar, etc.
- The main wild animals in this region include tiger, elephant, crocodile and deer, etc.