Item EN030002: Bacteria become resistant to antibiotics when a few individual resistant bacteria survive and reproduce, passing their resistance on to the next generation.

Which of the following correctly describes what happens when a population of bacteria becomes resistant to an antibiotic?  Note: a bacterium is one individual in a group of bacteria.

  1. During treatment with an antibiotic, each individual bacterium tries to become resistant to the antibiotic.  Only some are able to willingly become resistant, and these individuals survive to pass this trait to their offspring.
  2. During treatment with an antibiotic, all of the bacteria gradually become more resistant to the antibiotic the more they are exposed to it.  They all survive and pass this trait to their offspring.
  3. During treatment with an antibiotic, a population of bacteria usually dies.  Sometimes by chance, all members of the population become resistant at once, survive, and pass their resistance to their offspring.
  4. During treatment with an antibiotic, only those individual bacteria that already have a trait that helps them survive the effects of the antibiotic will live.  Their offspring in the next generation will also have this trait. 

Distribution of Responses

Chart showing distrubtion of responses for Item EN030002

Percent of students responding correctly

Overall26%
Grades 6–821%
Grades 9–1235%
Male28%
Female25%
Primary Language is English26%
Primary Language is not English26%

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