When the antibiotic penicillin was first introduced, it was immediately effective in combating
staphylococcus bacterial infections. After a number
of years, there were outbreaks of staphylococcal
infections that did not respond to treatment with
penicillin. The best explanation for this situation
is that
A. members of the original population of
bacteria that were penicillin resistant survived
and reproduced, creating a more resistant
population
B. the bacteria that survived exposure to
penicillin learned to avoid it
c. the bacteria that caused the new outbreaks
were from populations that had never been
exposed to penicillin
D. during each generation, the bacteria modified
their own DNA to increase their ability to
resist penicillin and passed this ability on to
their descendants