2. Which of the following is true about matter? a. Matter can only change states once or twice.
b. Water is the only kind of liquid matter that can become a solid.
c. Matter cannot be created or destroyed.
d. When water changes from a solid to a liquid, its total amount changes.

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?