When we ran our temperature trials, we kept lactose concentration and pH constant. Why is it important to make sure our experiment is controlled?

To establish the validity of the results obtained from the experiment.

Explanation:

An experiment is ultimately supposed to establish cause and effect relationships.

It is important to control all other variables that may affect the results of experiments. These are called extraneous variables. If these variables are not carefully controlled, it becomes impossible to accurately establish cause and effect relationships from the experiment.

The results of a controlled experiment is generally regarded as valid.