What determines the type of soil that created when it formed

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.

If a strand of dna has 35% thymine. what is the percentage of cytosine, adenine, guanine?

Which of the organisms listed below performs nitrogen fixation? a. legumes b. plants c. bacteria d. fungi