NO FAKE ANSWERS AND NO LINKS PLS. What does the atmosphere do?

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.

The changes that the students observed, rapid breathing and sweating, would be classified as a to a change in a system.

You are shown 2 samples of the earthes crust . the first is denser than the second . which most likley is oceanic crust