It'd be the second answer, a virus, which attacks the white blood cells.
I think someone relieve the heart rate of the heart rate during exercise
Answer:
Chloroplasts, which are filled with chlorophyll, which gives the green pigment in plants.
Explanation:
Answer:
Higher
Explanation:
Molecules such as oxygen move from a higher concentration to a lower concentration across a semi-permeable membrane. This process is called simple diffusion.
Therefore, for oxygen to leave the alveoli and enter the blood, there would need to be a higher concentration of oxygen inside the alveoli and a lower concentration of oxygen in the blood.