What is the leading federal agency in the united states that protects human health and safety?.

Mount saint helen the great lakes and death valley are physical features of the earth which scientific term describes these features

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 graph shows a trend in an ecosystem over time caused by increased pollution in the region. what can you conclude from the graph? a. there’s lower biodiversity among birds. b. there’s a higher reproductive rate among birds. c. there’s a significant decline in the number of producers. d. other types of animals were unaffected by pollution.