Which lists three units of an organ system in order from the simplest to the most complex? red blood cell → heart → tissue skeleton → bone → bone cell muscle cell → muscle tissue → stomach lung tissue → lung → circulatory system

Aplant has an egg with 34 chromosomes how many chromosomes does a leaf cell of that plant have

How are tumors cells different from normal cells

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.