A trilobite. Trilobites became extinct about 250 million years ago while a ammonite became extinct around the same time as dinosaurs(65 million years ago). You wouldn't find a human skull or a dinosaur footprint
Answer:
The differential equations and the boundary conditions(initial and final)are shown in the attachment
Biosphere- where living things exist
hydro- referring to just the water
geosphere-referring to entire thing
atmosphere- the gases in the air