Que relacion tiene las mutaciones con el proceso de seleccion natural?

What is histamine and what is its role in allergic reactions

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

What two fields of study provide the core information that is used to classify organisms?