Question

Which of the following conditions is most likely to lead to an increase in a field mouse population?

A. the arrival of another herbivorous mammal
B. the presence of a greater number of predator snakes
C. the disappearance of a bird species that preys on the mouse
D. the lack of adequate rainfall for plants in the mouse’s habitat

Answer 1

C. the disappearance of a bird species that preys on the mouse. If there are less/no predators(animals that feed on the mouse), then the mouse population will increase because they are not been eaten or reduced by that factor anymore.
The other options will only end up reducing the mouse population.