Question

Arthur is testing how well various types of disinfectants can kill E. coli bacteria. He starts with a Petri dish that is covered with a colony of E. coli. He puts exactly one milliliter of each different disinfectant at a different location on the Petri dish.

If a disinfectant works, it will eliminate the bacteria in the area in which it was placed. Two days later, Arthur will measure the amount of bacteria that has been cleared out by each disinfectant.

Which of the following is a variable in this experiment?

Answer 1

The variable in Arthur's experiment is the type of disinfectant used. It determines the effectiveness against E. coli by the amount of bacteria it can clear out.

Step-by-step explanation:

In Arthur's experiment testing the effectiveness of various disinfectants against E. coli, the variable would be the type of disinfectant used. Each disinfectant's efficacy in killing the bacteria is assessed by the amount of bacteria cleared out in the area where it was applied after two days. Essential aspects such as the concentration of the disinfectant, time of exposure, and the disinfectant’s mechanism of action influence the results of the experiment.

Answer 2

The E. coli bacteria. Hope this helps