As villi get taller the increases because...

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.

In the water cycle , when does water undergo a chemical change

At the age of 6 months, caleb was diagnosed with tay-sachs disease. as his primary care physician, what would you tell his parents about this disease?