A biologist whose interest lies primarily in the study of plants or animals can be called a naturalist, although these days it's more likely she'll be called a natural historian, a botanist, or a zoologist.
The infectious diseases are considered as emerging when their occurrences have increased in the past few years and could increase in the coming time like SARS, H1N1, or HIV/Aids.
On the other hand, the re-emerging infectious disorders are those, which were once considered as the major health issues globally or in a specific nation, and then got diminished drastically, however, are again turning into the health issues for a substantial ratio of the population like tuberculosis and malaria.
Answer:
A new mutation
Explanation:
A mutation refers to the random changes in the DNA of organisms. A mutation changes the allele and genotype frequencies by the introduction of a new allele in the gene pool.
However, mutations are not the major factor responsible for changes in the gene pool of a population as mutations are rare. The rate of mutations is very slow and does not allow it to serve as a major factor to change the allele and genotype frequencies.
The BRAIN. All of the senses send message to the Brain
