Casey, a microbiologist who has extensively observed escherichia coli (e. coli), wants to compare the death phase growth curve of e. coli after exposure to three different antibiotics: ampicillin, ceftriaxone, and levofloxacin. determine the order in which casey plans and implements a comparative investigation. rank the steps in the order in which they should occur in a scientific investigation. the first step should be placed in the highest position, at step 1, and the last step should be placed in the lowest position, at step 6.

a. casey reads background information on e. coli, the selected antibiotics, and other similar studies.
b. casey publishes the results and conclusions in a scientific journal.
c. casey takes bacterial counts every four hours after samples are exposed to one of the three different antibiotics.
d. casey develops a scientific hypothesis and designs an investigation to test it.