The change in velocity causes the waves to do what?

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 many volcanoes located along the edge of the pacific ocean make up the ring of fire. how does subduction play a role in the volcanic activity in the ring of fire?

Individuals do not compete directly for resources, but are prey for the same predator