It's called major histocompatibility complex protein
here is the answer of this qquestion
Answer: Option A "Choroid plexus".
Explanation:
Cerebrospinal fluid can be defined as the fluid that is found in the brain and spinal cord of human beings. It is a clear and colorless fluid.
The production of cerebrospinal fluid takes place by the specialized ependymal cells that lies in the choroid plexuses which is present in the ventricles of brain.
The amount of cerebrospinal fluid in a day is 500mL. This fluid acts as cushion that protects the brain from mechanical and immunological protection.
Hence, the correction answer is option A
True because excretory is like sweat and you sweat through your skin- more specifically the pores in your skin
4) stimulating the production of antibodies
so in future when you catch the same cold your body will be able to produce antibodies quickly because the memory cell remembers the antibodies that fights off the colds
i hope this helps and sorry if this is wrong