Which of the following characters is not a morphological variation?

1. Analyze the question The question asks which character is not a morphological variation. Morphological variations are differences in the visible external form or structure of organisms, such as shape, size and colour.

2. Explain the concept Variation among individuals of a species is classified in two main ways:

• Morphological (structural) variation: differences in physical appearance or body structure, for example height, skin colour, hair colour, nose shape and finger length.
• Physiological variation: differences in how the body functions, for example blood group, ability to roll the tongue, taste ability (PTC tasting) and sickle cell trait.

Tongue rolling is a physiological (functional) trait. It is the ability to curl the sides of the tongue upward, and it is controlled by genes. It is not a difference in outward body form.

3. Step-by-step solution

• A. Shape of the nose: a visible structural feature, so it is morphological.
• B. Colour of skin: visible appearance, so it is morphological.
• C. Colour of hair: visible appearance, so it is morphological.
• D. Tongue rolling: a functional ability, not a difference in body form, so it is not morphological.

4. Answer The correct option is D. tongue rolling.

5. Exam tip Ask yourself: "Can I tell just by looking at the person's body shape, size or colour?" If yes, it is morphological. If you have to test an ability, such as rolling the tongue, tasting PTC or finding the blood group, it is physiological. Remember: Morphology = Make-up you can see.