A. The south of Huaihe River in Qinling Mountains belongs to tropical and subtropical humid climate, with dense water network and extensive rice cultivation, so most flavor foods are made of rice.

B. As long as the geographical location is close, the same food culture will be formed.

C. "Sweet in the south and salty in the north" reflects the influence of climate and soil on people's eating habits and tastes to some extent.

D. In the humid and gloomy Sichuan Basin, boatmen and trackmen invented the cooking method of hot pot very early in order to drive away cold and dampness, and passed it on to this day.

Correct answer: The south of Huaihe River in Qinling Mountain belongs to tropical and subtropical humid climate, with dense water network and extensive rice cultivation, so rice is the raw material for flavor foods. "Sweet in the south and salty in the north" reflects the influence of climate and soil on people's eating habits and tastes to some extent. In the humid and dark Sichuan basin, boatmen and trackmen invented the cooking method of hot pot very early in order to drive away cold and dampness, and it has been passed down to this day.