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.
It is up to the individual to decide what they think is a significat change. Obviously a new species is huge change, but on the cellular level, evolution can happen in a matter of hours. The rate of evolution depends on how harsh the environment is and how necessary change is for survival.Physical adaptations take thousands, if not hundreds of thousands of years.volution can happen VERY fast.... study darwin's finches/// i saw a documentary of them and how a woman and her husband visit the galapagos islands every somethin amount of years(sorry i forgot :c) and the evolution of 13 species happened in the duration of their 1st visit and their 2nd.