How do ocean currents affect the paths of hurricanes?

Ascientist is studying muscle twitches in chicken quadriceps. to activate the muscle, he needs to provide stimulus to the

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.

Witch type of microscope is used to view very small cell components like proteins and dna?