Final answer:
When a previously sensitive organism develops resistance through spontaneous mutation or horizontal gene transfer, this is an example of resistance to antibiotics.
Step-by-step explanation:
When a previously sensitive organism develops resistance through spontaneous mutation or horizontal gene transfer, this is an example of resistance to antibiotics. Antibiotic resistance can occur when bacteria acquire genetic changes that allow them to survive and grow in the presence of antibiotics. These genetic changes can be acquired through mutations in the bacteria's own DNA or through horizontal gene transfer, where genes responsible for resistance are transferred from one bacterium to another.