Which of the following tools could have become cross-contaminated during the experiment if you had not cleaned them carefully between successive tests? a. spoon b. beaker c. stirring rod d. graduated cylinder e. distilled water in a spray bottle

Explanation:

When we are using spoon, beaker, stirring rod and graduated cylinder then they directly come in contact with the chemical we are using. Hence, if they are not washed thoroughly then chemicals remain deposited over them.

As a result, when successive test are performed using the same contaminated apparatuses then we do not get the desired results.

Whereas distilled water in a spray bottle if poured without touching or coming in contact with any kind of chemicals.

Hence, we can conclude that spoon, beaker, stirring rod and graduated cylinder are the tools that could have become cross-contaminated during the experiment if you had not cleaned them carefully between successive tests.