Which of the following is NOT an intrinsic factor?

• A. Age
• B. Corpulence
• C. Bacterial activity
• D. Air

Answer: (D)

Intrinsic factors are internal characteristics of a person or system—things that originate inside and influence outcomes regardless of the environment. Extrinsic factors come from outside, the surrounding environment.

Age is an internal attribute, reflecting time-based changes within the person. Corpulence is an internal characteristic, related to body composition. Bacterial activity is an internal biological process occurring within the organism’s context.

Air, by contrast, is external to the organism and represents an external condition. Because it comes from outside, it is not an intrinsic factor.