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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.

Dermal tissue in plants stores 1.extra food 2.transports water and nutrients 3.transports waste materials 4.is similar to epithelial cells in animals

Which of the following describes the difference in stimuli required to detect a difference between the stimuli? a. just noticeableb. signal detectionc. subliminald. top down