Factors that are the same throughout an experiment

• A. Variables
• B. Constants
• C. Controls
• D. Invariables

Answer: (B)

Keeping certain factors unchanged across the experiment helps reveal whether observed effects come from the variable you’re deliberately testing. Those factors are called constants. By holding things like temperature, lighting, equipment, or amounts of materials the same in every trial, you reduce other influences that could skew the result, so any change in the outcome can be more confidently linked to the factor you altered.

Think of it this way: you manipulate one variable—the one you want to study—while the rest stay the same. That way, differences in the dependent outcome come from that one change rather than from some other differing condition. A control is related but serves a specific purpose: it’s a baseline or standard used for comparison, and can be kept constant too, but constants are the everyday factors you keep identical to ensure a fair test. The term invariables isn’t a standard label in this context.