Which term describes the interaction where the combined effect is greater than the sum of the individual effects?

• A. Antagonistic
• B. Synergistic
• C. Additive
• D. Complementary

Answer: (B)

That describes synergy. When two factors interact so that their combined effect exceeds the sum of their individual effects, the interaction is synergistic. This means the two elements amplify each other in a way that the total outcome is greater than what you’d expect from simply adding their separate effects. For example, two treatments might each provide a certain amount of relief, but together they produce noticeably more relief than the sum of their individual effects. This isn’t the case with additive interactions, where the total equals the sum; or antagonistic interactions, where one factor reduces the other’s effect. Complementary actions can support a common outcome but don’t inherently imply surpassing the sum of effects.