Answer:
Mutation
Explanation:
A Mutation alters the genetic message carried by that gene as there are permanent changes in the nucleotide sequence of DNA or a DNA gene.
This can occur by base pairs substitution, deletion or insertion
The system of scientific naming or nomenclature is use to identify an organisms worldwide. The system of naming of an organism is introduced by Carolus Linnaeus. The scientific name of any organism is written by its genus name and species name. This is called binomial system of naming. While writing the scientific name of an organism, the name of the genus written first with a capital letter and the name of the species is written second with a small letter. When typed scientific name is in italics and when it is hand written the genus name and the species are to be underlined separately.
In the given example, the scientific name of orange-barred sulfur butterfly is <em>Phoebis philea</em>. <em>Phoebis</em> is its genus name and <em>philea</em> is the species name.
The addition of acetyl groups to histones is associated with chromatin condensation and and higher levels of gene expression
Random changes in allele frequency in a population are usually called genetic drift. The reason why this is the answer is because it is a very specific word which is used to describe exactly that - random changes in allele frequency.
All the other cases; answers, here aren't correct and don't apply.