Your friend has just told you that she has had strep throat for two
weeks. She said the doctor gave her an antibiotic that she took for
two weeks, but that the infection returned. Now, the doctor has
given her a second antibiotic that she must take for another two
weeks. Using your knowledge of natural selection, provide an
explanation to your friend for why she got sick again, and why the
doctor gave her the second antibiotic.