What are karyotypes? how are they different than punnett squares?

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.

Organisms may contain up to five levels of organization within their bodies. which level of organization is shown by the liver? a. tissue b. organ c. organism d. organ system

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?