Because an amino acid<span> cannot be </span><span>synthesized</span><span> by the organism, and it must be supplied in its diet.</span>
common descent means the evolutionary in biology and how they have something linked with their common ancestors.
Plates slid past each other
<span>Chlorofluorocarbons
(CFCs) chemicals contain carbon, chlorine and fluorine and is t so expensive at
the same time it’s not flammable, the reason why it is mainly used in business
such as refrigerators and plastics. However, these chemicals destroys our
stratosphere, the second layer of the Earth’s atmosphere and protects us by
blocking the ultraviolet radiation (UV Light). This type of radiation can seep
through organisms skins and can leave destructive effects on DNA molecules
which will also cause skin cancer.</span>
The answer is four bonds because they can use one electron for each bond.
Hope that helped :)
