1. Fossils and __________ are used to determine the differences between organisms.
2. All of Earth’s fossils organized by age is the _______________.
3. The idea that some animals are better equipped than others to survive in their environment than other is the basis of _____________________.
4. Scientific claims should be supported by facts and ____________.
5. Fish, amphibians, birds, reptiles, and mammals all have backbones, which means they are ________________.
