Which of the following statements about Nepal's geography is/are correct?

1. Nepal's topography, characterized by steep slopes and heavy monsoons, makes it highly vulnerable to landslides and floods.

2. The Koshi River, which flows through eastern Nepal, is known for its frequent changes in course, often leading to flash floods.

3. The Terai region of Nepal, located at a higher elevation, is less prone to flooding compared to the mid-hill regions.

How many of above statements is/are correct: