What is the purpose of a control in this experiment? Question 9 options:

The control is the tube that only has milk in it.

The control is the one tube that we know will show milk digestion.

The control is the one tube that we know will not show milk digestion.

The control is the only one the scientist changes.

I can't definitively answer this because I don't know the experiment, but I can help.

Explanation:

The "control group" of an experiment is like a dry simulation, where there is no variables changed across all the different trials you do. This is different from a dependent variable or an independent variable. Using your newfound knowledge of what a control group is you can automatically cross off the last option.

Since I cannot see what your experiment was I can't give you which of the top 3 answers it is however. You need to look at which one has no change.

If I were to blindly guess I would say the top option seems like the most likely answer.