Question

read the passage and answer the following question(s).
pneumonia: a global threat
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.
bacteria population that includes resistant bacterium
antibiotic is applied, bacteria without the resistant mutation die
the resistant bacterium multiplies and becomes more common
the entire infection evolves into a resistant strain
normal bacterium
dead bacterium
resistant bacterium
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?
□ bacteria that are better able to survive antibiotics pass on those traits to offspring.
□ individual bacterium can change their traits to become resistant to antibiotics.
□ the offspring of bacteria killed by antibiotics are best suited for survival.

Explanation:

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. In the context of drug - resistant bacteria, bacteria with traits that help them survive antibiotic exposure pass on these traits. Also, overuse and misuse of antibiotics create an environment that speeds up the mutation rate of bacteria, which is part of the natural selection process as bacteria adapt to the presence of drugs.

Answer:

1. Bacteria that are better able to survive antibiotics pass on those traits to offspring.
2. The overuse and misuse of antibiotics contribute to a faster - rate of mutation, helping the bacteria to modify at a quicker rate.