A tracheotomy is performed if enough air is not getting to the lungs, if the person cannot breathe without help, or is having problems with mucus and other secretions getting into the windpipe because of difficulty swallowing. There are many reasons why air cannot get to the lungs.
Trending Now. Answers. Best Answer: Yes, the smallest unit of evolution is the population. The reason is, the techical definition of evolution is change in allele frequency. You have to have a population in order to run the statistics to measure if there has been a change. Remember, a population does not necessarily mean all animals of one species.
According to Bohr, the amount of energy needed to move an electron from one zone to another is a fixed, finite amount. These zones are known as energy levels (or sometimes called electron shells). At the lowest energy level, the one closest to the atomic center, there is a single 1s orbital that can hold 2 electrons.