During winter, the pigment-producing genes of the arctic fox and other arctic animals do not function and the result is a white coat. this is an example of change due to environmental influence.

1. in what ways have non-native species been beneficial? 2. what are some of the hypotheses for the collapse of honeybee colonies? 3. distinguish between regional and functional extinction. 4. why is it difficult to measure background extinction rates? 5. what three factors are most important in causing extinction rates to climb?