They are used to define periods Geological time.
Answer: Check for the presence of antibodies in the blood
Explanation:
A person can only have antibodies for a virus if they got the virus in the first place
Facilitated diffusion therefore allows polar and charged molecules, such as carbohydrates, amino acids, nucleosides, and ions, to cross the plasma membrane. Two classes of proteins that mediate facilitated diffusion are generally distinguished: carrier proteins and channel proteins.
i think that the body does its just that the antibodies arent strong enough to combat the virus completely
