Arteries carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries , which carry blood to the lungs for oxygenation. Veins carry
deoxygenated blood to the heart but the pulmonary veins carry oxygenated blood).
all of the above can be considered ecosystems
The reason why the RNA has decrease stability compared to
DNA is because the DNA, is lacking a hydroxyl group in which making it more
stable than of the RNA, that is why RNA has decrease stability than the DNA.
A memory B cell is kinda of how it sounds it has a memory of what your body has fought before such as a virus and can stimulate a response quicker then the first time you encountered it.
If you lack memory B cells your body doesn't built up the same immune response when you come into contact with the virus again.
"Vaccination would prevent further disease" Incorrect, a vaccine lets you build up memory cells to combat the disease if you lack them you cannot build up a defense.
"Vaccination would not prevent further disease" Correct, a vaccine can be a dead version of a virus or parts of a virus that shows your body what to respond to quickly in the future. If you body cannot make memory b cells it wouldn't help to use a vaccine. Your body wouldn't keep a memory of it being bad.
"You would not produce antibodies" Even if your body does not remember a particular virus it does produce antibodies to combat it just not as quick or efficiantly as something it has come into contact with before and produced memory cells.
"You would over produce histamine" Incorrect, different process for that histamine.