Anew and effective antibiotic becomes widely used for a particular species of bacteria. after some time, an antibiotic-resistant strain of the bacteria becomes prevalent. which mechanism explains this phenomenon?
the bacteria undergoes genetic drift, leading to formation of a new gene pool and thus evolving a new characteristic.
although less common previously, the resistant strain becomes more prevalent due to natural selection.
the bacteria undergoes genetic flow, thus creating a new gene pool and evolving into a new species.

Use of Antibiotic is the main reason for development of antibiotic-resistant bacteria.
When a person is given the dose antibiotics, sensitive bacteria are killed, but resistant germs are sometimes left to grow and and increase in number.

Antibiotic resistance is the ability of an organism to stay unaffected by  the effects of antibiotics. Natural selection caused by random mutation is the main cause of Antibiotic resistance.

Hence,The right answer is : Option B: "Although less common previously, the resistant strain becomes more prevalent due to natural selection."

1.)dr. natterson- horowitz came to realize that their isn't much of a difference between animals and humans. just like humans, animals can suffer from illnesses and diseases like breast cancer, self injury, anxiety, and many more. she also discovered how they even treated and performed surgical procedures on animals just as if the animal it self were human. the los angeles zoo called dr. natterson- horowitz because they knew that she was a doctor and that  she would be able to recognize what was wrong with the gorilla. they knew that humans and gorillas were similar, so instead of calling another veterinarian, they called a doctor.

The apple is red lol