Adaptive immunity can be acquired during either 'naturally' (by infection) or 'artificially' (through deliberate actions such as vaccination). Adaptive immunity can also be classified as 'active' or 'passive'
<span>These are two antibiotics, I think not, do not take <span>them together.</span></span>
B, weakens the immune system
A. U.S. government website is most likely to contain information based upon empirical evidence.