A researcher wrote a program to simulate the number of mice in an environment that contains predators. The program uses the following procedures. Based on the code, which of the following assumptions is made in the simulation?

a The number of mice increases by 1 each day.

b The number of mice does not change from day to day.

c The number of predators increases by 1 each day.

d The number of predators does not change from day to day.