Here are the suggested words/phrases to fill in the blanks:

1. **terraced fields**
They are trying to turn the mountain slopes into terraced fields to help people in northern Viet Nam prevent cruel animals and floods.

2. **unique features**
The unique features of the Muong people include their rich cultural traditions and unique handicrafts.

3. **ethnic groups**
Ethnic groups of Viet Nam preserve their unique customs and contribute to the nation's cultural picture.

4. **musical instruments**
The bamboo flute is one of the most popular musical instruments of Viet Nam.

5. **traditional**
Visiting wife’s parents – on the 2nd day of the Lunar New Year – is a custom of Tay and Nung people and is considered traditional.

6. **minority groups**
The Hmong minority groups have a rich cultural heritage and distinctive traditions.

7. **livestock**
The farmer raised healthy livestock to provide meat and dairy products for the local community.