<span>The geologic time scale is divided into periods, which are then divided into epochs, which are further divided into ages. For example, the time of the dinosaurs lasted 3 periods (Triassic, Jurassic, Cretaceous), each period had 3 epochs (late, early, middle), and each age fit into one of those. Many epochs have more than 1 age associated with them.
As for the basis for differentiating the eras, I'm not so sure. The only one I can say for sure is the end of the Cretaceous, which is when the dinosaurs suddenly became extinct due to a meteor impact. I think the divisions are based on significant, global-scale events that changed the world.
Sorry its so long but that the answer i think >:) ur welcome
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The formation oil, that is, sweet crude, is typically that accumulate on the seafloor and "kitchen" of the geothermal gradient to be altered in petroleum products.while <span>Most of the </span>coal<span> we use now was </span>formed<span> about 300 million years ago, when much of the </span>earth<span> was covered by steamy swamps.
hope that helped</span>
B. To contrast between the high and low concentration of molecules.
for example a solution with a higher solute concentration than the inside of the cell is called hypertonic
It is called THERAPEUTIC INDEX. Therapeutic index is the comparison of the amount of a particular drug that causes the desired therapeutic effects and the amount that causes toxicity. The index can be low or high. A drug with a low therapeutic index will require only a small increase in dose to produce toxic effects in users.
At the center of the cloud, more weight of the gas molecules are present.
The mass or weight at the center of the cloud increases when the gas molecules group together in a molecular cloud because more gas molecules are present at the center which combines with each other leads to heavier weight of gas molecules. The combination of gas molecules make the center of the molecular cloud denser as compared to other parts of the cloud so we can conclude that increase in mass occur at the center of the cloud.
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