Answer:
2.7 billion
Explanation:
This period is referred to as the Great Oxygenation Event. This period saw the evolution of photosynthetic organisms (cyanobacteria) that utilized carbon dioxide (that dominated the atmosphere then) and sunlight to manufacture their energy molecules-glucose. Photosynthesis produces oxygen as a byproduct that is evolved into the atmosphere. As these photosynthetic organisms proliferated on earth, the atmosphere composition changed to become partly dominated by oxygen (which is an oxidaton agent) with less and less carbon dioxide.
Answer:
Evolution is a process that results in changes in the genetic material of a population over time. Evolution reflects the adaptations of organisms to their changing environments and can result in altered genes, novel traits, and new species.
Explanation:
Simple Diffusion Across the Cell (Plasma) Membrane. The structure of the lipid bi-layer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.
No! After the dinosaurs died out, nearly 65 million years passed before people appeared on Earth. However, small mammals (including shrew-sized primates) were alive at the time of the dinosaurs. Many scientists who study dinosaurs (vertebrate paleontologists) now think that birds are direct descendants of one line of carnivorous dinosaurs, and some consider that they in fact represent modern living dinosaurs. This theory remains under discussion and shows that there is still much we don't know about dinosaurs.
Proximal converted tubula
