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Question

The arctic fox inhabits northern areas of North America. The same arctic fox is shown in the drawing at different times of the year.

What causes this change in fur color?
The alleles for fur color change as the arctic fox grows older.
The arctic fox has two traits for fur color that are determined at birth.
Gene expression for fur color is regulated by temperature.
Gene expression for fur color is regulated by latitude.

Answer 1

The change in fur color of the arctic fox is primarily caused by the regulation of gene expression in response to environmental factors, particularly temperature. Therefore, the correct explanation is:

Gene expression for fur color is regulated by temperature.

As the seasons change, the fur color of the arctic fox changes from brown or gray in the summer to white in the winter, which helps it blend into its snowy surroundings and provides camouflage against predators and prey. This adaptation is influenced by the temperature and length of daylight, triggering changes in the fur color through shifts in gene expression rather than changes in the underlying alleles or genetic traits.