How can taking antibiotics when they are not needed add to the problem of resistance to antibiotics?

Taking antibiotics when they are not needed can contribute to antibiotic resistance by allowing bacteria to adapt and evolve in response to the selective pressure imposed by these drugs. When antibiotics are used unnecessarily, they can kill susceptible bacteria, while resistant strains survive and multiply. This leads to the proliferation of resistant bacteria, making infections harder to treat and increasing the risk of spread to others. Ultimately, this cycle threatens the effectiveness of antibiotics, compromising public health.