n carrying out normal activities, cells use oxygen and produce carbon dioxide. The concentration of oxygen is higher in the bloo
d than inside the cell, so oxygen moves into the cell. Similarly, carbon dioxide moves out of the cell into the blood because the concentration of carbon dioxide inside the cell is greater than the concentration outside the cell. How are the small molecules of oxygen and carbon dioxide moving through the cell membrane?
by injecting the weakened virus into your body it helps the body familiarize and create the right antiviruses for the virus so that if it ever gets in your system you can actually fight it.
