I'm very Lay in biology, but I was studying the subject and the following problem emerged:
It's known that all bacteria are unicellular beings, and their reproduction it's asexual. Besides of that the indiscriminate use of antibiotics leads to the development of more severe infections, because of a process of natural selection and survival of the most resistant. How do we explain this process considering that asexual reproduction doesn't generate genetic variability, besides mutation? Why do we have this differences, if asexual reproduction generates clones?