Sleep is an example.
Circadian rythms are biological processes that repeats itself within a certain time frame, as sleep repeats itself approximately once every day.
Controls what substances can move in and out of the cell. it also protects the cell from its surroundings.
The answer is oil.
The United States' fossil shortage of oil makes the country dependent on outside sources. Mineral oil such as crude oil or commonly known as petroleum came from the ancient fossilized organic materials. This resource is limited. The US is now facing a shortage in oil and becoming dependent to some countries such as middle-east countries.
Both have phosphate-pentose back bone, as well as both have adenine, cytosine and guanine bases.
