I believe A is the most correct (i assume it's about antibiotics - they actually DO harm our immune system in some way).
B is partially correct because, the colds indeed should be treated by anti-viral medication (because the virus is a cause of typical cold) but using antibiotics during recovery is needed only when an additional bacterial infection occurs as a complication after the viral infection. and it doesn't happen very often.
C - what works? antibiotics doesn't work for viral infections (colds). anti-viral medication do.
D i won't discuss.
I am sorry for a so long answer. but your question is so linguistically twisted that i am not sure which of the following choices is actually correct because of a big amount of mistakes.
B double helix and linked with hydrogen bonds
I believe the correct answer from the choices listed above is the second option. The evidence that would be most useful for making this determination would be to u<span>se radiocarbon dating to determine the age of the rock underlying the ecosystem.</span>. Succession<span> is usually initiated by a significant disturbance of an existing community. Hope this answers the question.</span>
C- the cell is preforming mitosis
