A discontinuous morphological variation often used in crime detection is the

Analyze the question: The question asks for a discontinuous variation that is morphological (concerning physical form or structure) and is used in crime detection.

Concept:

• Continuous variation: Traits show a full range of values between two extremes, with no clear-cut categories. They are usually controlled by many genes and are affected by the environment. Examples are height, weight, and skin colour.
• Discontinuous variation: Traits fall into distinct categories with no intermediates. They are usually controlled by one or a few genes and are little affected by the environment. Examples are blood groups, the ability to roll the tongue, and fingerprint patterns.
• Morphological variation: Differences in visible physical form or structure. Blood group is a physiological or biochemical trait, not a morphological one.

Step-by-step solution:

• A. Skin colour: This is continuous, because there are many shades. Eliminate.
• B. Blood group: This is discontinuous (A, B, AB, O) and is used in forensics. However, it is a biochemical or physiological trait, not a morphological one, and it is not unique to an individual. Eliminate.
• C. Finger prints: The patterns (loops, whorls, arches) are distinct, visible structural features, so they are morphological. They fall into distinct categories, so they are discontinuous. They are unique to each person and are the classic tool for identifying criminals. This fits all the requirements.
• D. Eye colour: This shows a gradation of shades, so it is largely continuous. It is also not a standard tool in crime detection. Eliminate.

Answer: **C.

Tip: For "discontinuous variation," think of traits you can sort into clear groups, such as blood group, fingerprint type, tongue rolling, and sickle-cell genotype. If the question says "morphological" and "crime detection," fingerprints are the usual answer. Blood group is discontinuous too, but it is a physiological trait rather than a morphological one.