There are all sorts of ways to reconstruct the history of life on Earth. Pinning down when specific events occurred is often tricky, though. For this, biologists depend mainly on dating the rocks in which fossils are found, and by looking at the “molecular clocks” in the DNA of living organisms.
There are problems with each of these methods. The fossil record is like a movie with most of the frames cut out. Because it is so incomplete, it can be difficult to establish exactly when particular evolutionary changes happened.
Modern genetics allows scientists to measure how different species are from each other at a molecular level, and thus to estimate how much time has passed since a single lineage split into different species. Confounding factors rack up for species that are very distantly related, making the earlier dates more uncertain.
These difficulties mean that the dates in the timeline should be taken as approximate. As a general rule, they become more uncertain the further back along the geological timescale we look. Dates that are very uncertain are marked with a question mark.
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The freshwater trout requires a lower salt ions to function.
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Mice and Rabbits
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the other ones would be for omnivores
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Electric is the way so ive got to ask you
Do You Know Da Way
Because Dis Is the way :)
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The four nitrogen bases that are found in deoxyribonucleic acid (DNA) are adenine, cytosine, guanine, and thymine.
Thymine and cytosine comprise of one -carbon nitrogen ring and also called pyrimidines, while two carbon nitrogen ring is present in adenine and guanine and also called purines. Purines has larger in size because of extra carbon nitrogen ring.
