Wild foxes are aggressive and unfriendly to humans. However, russian scientists have worked since the 1950s to breed a domesticated version of the silver fox. Each year, scientists choose the tamest foxes to mate together. Gradually, the foxes are becoming more like dogs. They are much more friendly and playful than wild foxes. What technique is used to increase desirable traits in domesticated animals through breeding?

a. artificial selection

b. natural selection

c. genome selection

d. cloning selection