Respuesta :
If want a direct answer it would be the decrease in mice, but if you want to get technical the decrease in grain spills caused mice to leave so that would be the indirect cause
Answer: Due to decrease in number of mice( food for snakes)
Explanation:
Farmer used new method to prevent the grains from getting spoiled. This method reduced the number of mice in the field.
The decrease in the number of mice will ultimately decrease the number of snakes.
So, the likely reason for the decrease in population of the snakes are decrease in the number of mice.