If constants aren't given in an experiment, what can be constant in the experiment?

Anything in an experiment that remains unchanged.

Explanation:

An example could be the temperature of the laboratory room. If there is something that has an effect on an experiment that is not variable, it is a constant. Another constant could be, say, if you were doing calculations with the same amount and kind of fluid throughout the experiment, then that fluid would also be a constant.

labor day, patriot day, leaves start to change colors then fall from the tree