Which of the following is an example of variation?

Step 1: Analyze the question The question asks which option is an example of variation. Variation means the differences that exist among individuals of the same species.

Step 2: Explain the concept Variation is of two types:

• Continuous variation: a range of values with no clear-cut groups. Examples are height, weight and skin colour.
• Discontinuous variation: distinct groups with no in-between forms. Examples are tongue rolling, blood groups (A, B, AB, O), sickle cell trait, and the ability to taste PTC.

Step 3: Check each option

• A. Blood: Blood is a tissue, not a variation in itself. Only the blood group would be an example of variation, so "blood" on its own does not fit.
• B. Tongue rolling: Some people can roll their tongue into a U-shape and others cannot. This is a clear-cut difference among individuals of the same species, so it is a classic example of discontinuous variation.
• C. Reproduction: This is a characteristic of all living things (a life process), not a variation.
• D. Growth: This is also a life process common to all living organisms, not a variation.

Step 4: Answer The correct option is B. Tongue rolling.

Tip: For variation questions, look for a trait that differs from person to person, such as tongue rolling, blood group, fingerprints, height or skin colour. Life processes such as growth, reproduction, respiration and excretion are shared by all living things, so they are not variations.