What actually cause us to snore. and how can i prevent it. sometimes at night my mouth remains open and very dry up to the trought?

Snoring: 70% of the time, this is due to the soft palate vibrating against the back of the throat. Throat tissues can become lax over time with less elasticity, making snoring more common with age. There can be resistance to breathing through the nose or mouth due to a variety of anatomic causes which restrict airflow, causing vibration. Nasal strips, snore guards, and better pillows can help. See an ENT.