The geologist time scale was formed when scientists studied rock layers and index fossils worldwide. With this information, they placed Earth's rocks in order by relative age. Later, radioactive dating helped determine the exact age of the divisons in the geologic time scale.
This scale is organized by the 4.6 billion years of earth's history into sections based on important changes seen in the geologic record. The largest intervals are called eons, with each eon containing many millions of years.
In precambarian time the processes that affect Earth's surface have lessened the erosion on the surface. Earth was being hit by meteorites every second. Now there is water erosion and there wasn't back then. The surface changes have lessened over time.
Nucleotides are being named or classified by their bases. They are adenine, cytosine, guanine, thymine and uracil. Nucleotides are organic molecules that serve as the monomers, or subunits, of nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
<span>Fats, oils and cholesterol are all types of lipids.Lipids are biomolecules that consist in long chains of carbons and hydrogen, insolubles in water (becauise they are not polar). Many lipids have in common the functional group corboxilic, COOH. Cholesterol, fats and oils all have carboxlic group. </span>