1 If living in an area with frequent thunderstorms, consider buying a lightning protector. 2  These cost between $35 and $55. 3  Keep in mind that an invisible fence doesn't keep other dogs, animals or people out of the yard. If living in an area with frequent thunderstorms, consider buying a lightning protector. 2  These cost between $35 and $55. 3  Keep in mind that an invisible fence doesn't keep other dogs, animals or people out of the yard.
Carbon is essential for the survival, growth and reproduction of living things. It is a finite resource that comes in different forms and transfers from living to non-living things in various ways. Carbon stays balanced with other chemical reactions in the air and bodies of water through the carbon cycle.
Carbon is the chemical basis for most of the molecules that are important to maintaining life. These molecules include carbohydrates, lipids (the category that includes fats), proteins and nucleic acids (made famous by DNA, the chemical that contains our genetic code).