Which of the following is NOT an application of variation?

Analyze the question: We need the option that is NOT a practical application of variation (differences among individuals of a species).

Concept: Variation refers to differences among members of the same species. Its practical applications include:

• Blood transfusion: blood groups (A, B, AB, O) vary, so donor and recipient must be matched.
• Crime detection: fingerprints, DNA profiles and blood types differ between individuals, so they can identify suspects.
• Determination of paternity: blood groups and DNA profiles are inherited, so they can show whether a man could be a child's father.
• Marriage counseling: genotype variation (e.g., AA, AS, SS) is used to advise couples on the risk of sickle cell disease in their children. This is a real application of variation.

Adaptation for survival: This is a consequence or biological significance of variation. Variation gives organisms traits that help them survive in their environment, and natural selection acts on it. It is not a human-applied use of variation in the way the other four are.

Working through the options:

• A. Adaptation for survival: a natural importance of variation, not a practical application.
• B. Blood transfusion: application.
• C. Crime detection: application.
• D. Paternity determination: application.
• E. Marriage counseling: application (genotype compatibility).

Tip: In NECO and JAMB, "applications of variation" usually means human uses such as blood grouping, forensic identification, paternity tests and genotype counseling. Natural processes like adaptation and evolution are results of variation, not applications.