Question

doctors use antibiotics to kill harmful bacteria. bacteria with antibiotic resistance can survive more doses of antibiotics than bacteria without resistance. the table shows how the percentage of salmonella bacteria that are resistant to a type of antibiotic changed from 2000 to 2011.

year	percent resistance
2001	30
2002	24
2003	40
2004	42
2005	48
2006	55
2007	62
2008	59
2009	60
2010	69
2011	71

which statement is the best explanation for what is happening in the salmonella bacteria population over time?
a. more bacteria are choosing to develop resistance to antibiotics.
b. the strength of antibiotics has decreased, allowing the bacteria population to live longer.
c. resistant bacteria are more likely to reproduce, so resistance is becoming more common.
d. more frequent travel among individuals is causing an increase in the number of people that bacteria infect.

Explanation:

Bacteria with antibiotic - resistance have a survival advantage. They are more likely to survive antibiotic treatments and reproduce. Over time, this leads to an increase in the proportion of resistant bacteria in the population. Option A is incorrect as bacteria do not 'choose' to develop resistance; it is a result of genetic mutations and natural selection. Option B is not supported by the data; there is no indication of a decrease in antibiotic strength. Option D is not relevant to the increase in antibiotic - resistance shown in the table.

Answer:

C. Resistant bacteria are more likely to reproduce, so resistance is becoming more common.