The cell membrane forms a protective barrier between the external and internal environments. it is referred to as because it allows some substances to cross more easily than others and blocks other substances from crossing into the cell. a) impermeable b) a fluid mosaic c) a plasma membrane d) selectively permeable

Is citizens were comfortable with their detachment from england and had no interest in going to war

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.

When a cell is in a solution that has the same concentration of water and solutes as its cytoplasm, the cell is said to be in a(n) solution. a. isotonic b. hypotonic c. hypertonic b. facilitated