Question

which statement best explains the change in the mouse population?
a the light - colored mice are easier to see in the environment, so the bird preys upon them more, leaving a larger percentage of dark - colored mice to survive and reproduce.
b the bird prefers the dark - colored mice, so their reproductive rate decreased, leaving a larger percentage of light - colored mice for the bird to eat.
c the reproductive rate of the dark - colored mice increased to replace the number of mice taken by the bird.
d the bird preys upon the smallest mice in the population, so only the larger mice survive and reproduce.

Explanation:

Natural selection occurs when organisms with traits better suited to their environment survive and reproduce more successfully. In this case, light - colored mice are more visible (less camouflaged) in the environment, making them easier prey for the bird. As a result, dark - colored mice, which are better camouflaged (more suited to the environment in terms of avoiding predation), have a higher chance of surviving and reproducing. Option A correctly describes this process of natural selection based on camouflage and predation pressure. Option B is incorrect because it claims the bird prefers dark - colored mice, which would not lead to an increase in dark - colored mice in the population. Option C is wrong as it implies a conscious increase in reproductive rate of dark - colored mice to replace those taken by the bird, rather than natural selection. Option D is incorrect as it focuses on size (smallest vs larger) rather than color (light - colored vs dark - colored) which is the trait relevant to the question about the change in the mouse population.

Answer:

A. The light - colored mice are easier to see in the environment, so the bird preys upon them more, leaving a larger percentage of dark - colored mice to survive and reproduce.