Final answer:
The overuse of antibiotics has resulted in the natural selection of resistant forms of bacteria. It also leads to the spread of antibiotic resistance and contributes to the development of resistant bacteria in livestock.
Step-by-step explanation:
The overuse of antibiotics has resulted in several problems, one of which is the natural selection of resistant forms of bacteria. When antibiotics are used excessively, they kill most of the infecting bacteria but allow the resistant forms to survive and reproduce. This results in an increase in the proportion of resistant forms over non-resistant ones.
Another problem associated with the overuse of antibiotics is the spread of antibiotic resistance. New forms of antibiotic resistance can cross international boundaries and spread between continents with ease. Antibiotic-resistant bacteria, such as MRSA, can cause serious and life-threatening infections that are difficult to treat.
Furthermore, the excessive use of antibiotics in livestock is a significant concern. Animals that are given antibiotics in their feed promote bacterial resistance. The routine use of antibiotics in animal agriculture contributes to the development and spread of antibiotic-resistant bacteria.