A Level Biology Practice Exam

Which of the following describes continuous variation?

1. A characteristic with distinct categories of values

2. A characteristic that can take any value within a range

3. A characteristic that remains constant across generations

4. A characteristic that is influenced solely by environmental factors

The correct answer is: A characteristic that can take any value within a range

Continuous variation describes characteristics that can take any value within a specified range, resulting in a smooth gradient of traits rather than discrete categories. This form of variation is often observed in quantitative traits, such as height, skin color, or weight, where individuals exhibit a wide spectrum rather than falling into clear-cut groups. This variation is typically influenced by multiple genes, known as polygenic inheritance, and is often affected by environmental factors as well. As a result, you can observe traits that shift gradually from one extreme to another rather than being limited to set categories. In contrast, the other options do not accurately characterize continuous variation. Distinct categories indicate discontinuous variation, a situation where traits fall into specific groups without intermediate forms. A characteristic that remains constant across generations suggests stability and lack of variation, which does not pertain to the concept of continuous variation. Lastly, emphasizing that a characteristic is influenced solely by environmental factors overlooks the significant genetic contribution often present in traits that demonstrate continuous variation.