Explanation: The best explanation for the bacteria surviving the second treatment with the same antibiotic is the development of antibiotic resistance.
When the scientist initially treated the colony of bacteria with the antibiotic, most of the bacteria died. However, it is common for a small percentage of bacteria to have natural variations or mutations in their genetic material. These genetic variations can confer resistance to the antibiotic.
During the first treatment, the susceptible bacteria were killed, but the resistant bacteria survived because they were not affected by the antibiotic. As a result, the surviving resistant bacteria were able to reproduce and pass on their resistant traits to their offspring.
In the second treatment with the same antibiotic, the majority of the bacteria were now resistant. Since the antibiotic targets specific mechanisms or structures within the bacteria that are essential for their survival, the resistant bacteria were able to withstand the antibiotic's effects and continue to thrive.
This phenomenon, known as antibiotic resistance, is a significant concern in healthcare and the agricultural industry. It occurs when bacteria evolve and adapt to survive exposure to antibiotics, rendering the drugs less effective in treating infections.
Therefore, the best explanation for the bacteria surviving the second treatment with the same antibiotic is the development of antibiotic resistance among the bacterial population