3tc is an antiretroviral treatment used to prevent hiv infection from becoming aids. after treatment with 3tc, the hiv population in a patient consists entirely of 3tc-resistant virus particles. what best explain this phenomenon? a) hiv can change its surface proteins through mutations and resist vaccines. b) the patient became re-infected with 3tc-resistant viruses after the initial exposure. c) the drug caused rna changes to occur, creating a resistance to the once-applicable drug. d) a few drug-resistant viruses were present at the start of treatment and selective pressures increased their frequency.

D

Explanation:

3TC is an antiretroviral treatment used to prevent HIV infection from becoming AIDS. After treatment with 3TC, the HIV population in a patient consists entirely of 3TC-resistant virus particles. What best explain this phenomenon?

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.

well the answer is 2!