Question

pneumonia is a lung infection that can be caused by several strains of bacteria. this type of infection can be treated with antibiotics, such as penicillin. it can also be prevented through vaccines for bacteria that can cause pneumonia. when antibiotics and vaccines were introduced, infections were greatly reduced; however, bacteria change to survive the antibiotics and vaccines. the most common change happens through mutations. the rate of mutations in pneumonia - causing bacteria occurs approximately once every 15 weeks. these mutations help bacteria develop resistance to antibiotics. the number of resistant bacteria then increases due to natural selection. the diagram shows a bacterial population that is treated with an antibiotic.
the overuse and misuse of antibiotics can also cause drug resistance. the overuse of antibiotics contributes to a faster rate of mutation, helping the bacteria to modify at a quicker rate. by the time newer vaccines or drugs are introduced, some bacteria have already developed resistance. misusing antibiotics, by not completing a prescribed course, contributes to the likelihood that more bacteria will become resistant.
resistant bacteria make it harder and more expensive to treat infections. this is a major threat to public health. one of the newer approaches to prevent the spread of disease is by providing adequate nutrition, sanitation, and addressing environmental factors. antibiotic treatment can achieve a better outcome when two or more drugs are combined during treatment. new drugs and vaccines are also being developed to prevent and treat future infections.
which two statements describe how natural selection affects drug - resistant bacteria?
a. bacteria that are better able to survive antibiotics pass on those traits to offspring.
b. individual bacteria can change their traits to become resistant to antibiotics.
c. the offspring of bacteria killed by antibiotics are best suited for survival.
d. the first bacteria are the least likely to survive a treatment of antibiotics.
e. traits that are beneficial increase in frequency across a population of bacteria.

Explanation:

Natural selection favors bacteria with antibiotic - resistant traits. Resistant bacteria survive and reproduce, passing on these traits, increasing their frequency in the population.

Answer:

A. Bacteria that are better - able to survive antibiotics pass on those traits to offspring; E. Traits that are beneficial increase in frequency across a population of bacteria