Size, colour and fingerprints are examples of ______

Analyze the question: It asks which type of variation is shown by size, colour and fingerprints. These are all features of the outward form, or structure, of an organism.

Concept: Variation is the difference between individuals of the same species. It can be classified in different ways:

• Morphological variation: differences in physical form or structure, such as height, size, skin colour and fingerprint patterns.
• Physiological variation: differences in how the body functions, such as blood group, metabolic rate, and the ability to roll the tongue or taste PTC.
• Discontinuous variation: distinct categories with no intermediates, such as blood groups (A, B, AB, O) and tongue rolling. Size is not an example, because it varies continuously (height, for instance, has many intermediate values).
• Adaptive variation: differences that help an organism survive in its environment.

Solution:

1. Size (height, weight) is a structural, measurable feature, so it is morphological.
2. Colour (skin, eye or coat colour) is an external physical feature, so it is morphological.
3. Fingerprints are patterns of ridges on the skin, which is also structure, so they are morphological.
4. Discontinuous variation (B) fails because size is typically continuous.
5. Physiological variation (A) concerns body functions, not appearance or structure.
6. Adaptive variation (D) is about survival advantage, which the question does not describe.

All three examples describe physical form, so the answer is morphological variation.

Answer: C. Morphological variation

Tip: "Morpho" means form or shape. If the trait can be seen or measured on the outside of the body, think morphological. If it concerns how the body works, such as blood group or enzyme activity, think physiological.