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.

Can you identify which of the following groups of organisms are, or are not, populations? a. the american bison (bison bison) and grey wolves (canis lupus) currently living in yellowstone national parkb. all of the rainbow trout (oncorhynchus mykiss that) that have ever lived in lake eriec. the group of american bison (bison bison) currently living in yellowstone national parkd. a group of calliope hummingbirds (selasphorus calliope) and a group of rufous hummingbirds (selasphorus rufus) living in the same new hampshire woodse. the northern cardinals (cardinalis cardinalis) living on opposite shores of lake champlain f. all of the whales currently living in the atlantic ocean off cape cod, massachusetts

Nasa scientists must work together to make sure that everything is correct and accounted for when launching a shuttle. besides a physicist, what other type of scientist would be in making sure that the shuttle has the appropriate type and amount of fuel to reach its destination?

Which of the following shows the correct order in which light information travels through the eye? (2 points) lens, pupil, retina, optic nerve pupil, lens, retina, optic nerve pupil, lens, optic nerve, retina lens, pupil, optic nerve, retina