1. What are the two basic groups of organisms

How does secondary succession differ from primary succession?

The diagram shows a chicken embryo and a human embryo

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?