Can sunlight change the distribution of traits in a population?.

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.

The tendency to seek out individuals who represent the same level of physical attractiveness as ourselves is explained as

Which situation is the best example of opportunity cost? a country chooses to produce bananas instead of wheat. a country chooses to invest in manufacturing and agriculture. a country chooses to specialize in producing paper products. a country chooses to export all of its products.