Natural Selection in Action - Resistance in Bacteria

Gap-fill exercise

Natural selection results in to the environment being and passed on. So, with time, the will become better adapted.
If a person has a infection, some of the bacteria will have more to antibiotics.
When the person starts their course of , many bacteria will die quickly. However a few with more will still be alive, even though the person feels quite well. If the person then stops taking the antibiotics, then the more resistant bacteria will . Over time this can lead to strains of bacteria that are very resistant to many antibiotics - .
If the person had continued to take their antibiotic course, even the resistant ones would eventually have been .