How can a parasite influence a population?

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.

Which of these is not a nucleotide base found in dna?

Consider the venn diagram of plant reproduction. where in this image, areas a - d, would you insert the picture of the orange lily?