Variations within a species are an important part of charles darwin's theory of evolution. choose the statement that can be explained by individual variation.

a.) the food source in a lake is not enough to support the bass population, but it can support the trout.
b.) a population of brown bears has doubled in the past 10 years.
c.) owls and foxes compete fiercely against each other for small rodents in their habitat.
d.) brightly colored cardinals are better able to survive and to reproduce than darker cardinals.

The correct answer would be D.) Brightly colored cardinals are better able to survive and to reproduce than darker cardinals.

Within a population, organisms often exhibit variations which can be inherited. These variations may include the color of skin, hair, and eyes, antibiotic resistance et cetera.

These variations help in the survival of a population through natural selection when they face a change in environment.

The organisms with beneficial variations tend to survive and reproduce.

The benefited variation is passed on to the offspring and thus help in the survival of the population.

In option D, cardinals have two variations; dark color and bright color out of which, bright color provides survival benefits to the population.

D is the answer.