Proto-oncogenes proto-oncogenes normally suppress tumor growth are produced by somatic mutations induced by carcinogenic substances are underexpressed in cancer cells stimulate normal cell growth and division were initially introduced into eukaryotic cells by retroviruses

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.

Iron reacts with oxygen to produce iron oxide (rust). this reaction is represented in an equation as 4fe + xo2 → 2fe2o3. identify the value of x that will balance the equation.

Which description provides the best objective summary of the article in the passage?