(Q002) The Earth's atmosphere Group of answer choices began as nitrogen and oxygen, left over from the solar nebula. acquires its carbon dioxide from photosynthesis by green plants. gets warmer as its carbon dioxide concentration goes down. became more oxygen-rich during the Proterozoic, after the evolution of photosynthetic organisms in the Archean.

Wich level of organization includes all the other levels or organizations

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Use the drop-down menus to match each part of the scenario to the correct scientific practice. akira records the speed of a reaction without a catalyst and then with a catalyst. akira creates a reaction without a catalyst and repeats the reaction with a catalyst. akira turns in a written lab report to his science teacher. akira wonders, "will adding a catalyst speed up this chemical reaction? " akira writes in his notes that adding a catalyst sped up the chemical reaction because the catalyst lowers the activation energy needed to get the reaction started.