Approximately how long does the menstrual cycle last if fertilization does not take place?.

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.

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

Which of these definitions have been paired with the correct type of cell?