About how long does one cell cycle last in fertilized clam eggs

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.

Prompt compare the three types of volcanic mountains in terms of shape, type of eruption, and the minerals that make up the volcano

At which location in earth’s interior does the top density continue to increase as thickness decreases?