Give the term for the factors that remain the same?

Question

Give the term for the factors that remain the same?

Answer 1

Constant, perhaps?

In an experiment, there may be multiple "things" that can change.  When we design an experiment it is useful to vary one variable at a time and keep the rest constant.

Answer 2

How about "controls"?

In an experiment, the factors that must remain the same between trials of a variable are called controls.