The chemical originally contained in aerosol propellants that is thought to have contributed to the depletion of the ozone layer is the chlorofluorocarbons or the CFCs. These are nonflammable and nontoxic substances that has carbon, chlorine and fluorine in their structure. These substances are used as propellants, solvents and as refrigerants. However, it was found from researches that these substances would contribute to the depletion of the ozone layer in the atmosphere which is why under the Montreal Protocol, the use of these are banned and other alternatives are being used now in replace with the CFC. One alternative used is the <span>hydrofluorocarbons.</span>
When researchers examine these damaged nerves, they find that the myelin insulation is often gone and the axons are destroyed. These changes prevent nerves from transmitting messages properly.
A
The phanerozoic geologic era is divided into three and the paleozoic era is the first among them. The paleozoic era occurred about 902 million years ago and it divided into six different periods. It was a time of dramatic changes in term of climate, geology and evolution.
During the first period of the paleozoic era large number of creatures evolved, this is called Cambrian explosion. Most of the biological classes that are still prevalent today such as primitive fish and coral were evolved during this era. Mass evolution of fish also occured during this era. <span />
Aristarchus’s model not accepted because at that time it was believed that the earth was at the center of the universe.
<h3>What is Aristarchus’s model?</h3>
Aristarchus make a model by placing the place of the Sun in the middle of the solar system and placed the planets around the Sun.
So we can conclude that Aristarchus’s model not accepted because of the believed that the earth was at the center of the universe.
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Answer:
El ciclo celular es la replicación y reproducción de las células, ya sea en eucariotas o procariotas. Es importante para los organismos de diferentes formas, pero en general les permite sobrevivir. ... Los cigotos también dependen del ciclo celular para formar sus muchas células con el fin de producir un organismo bebé al final de su proceso.
Explanation:
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