One of this is not a continuous variation

Explanation

This Biology question is asking about continuous variation and which of the options listed is not an example of it. Continuous variation is the variation of traits that show a range of values, such as height or weight. The question asks which one of the options is not an example of continuous variation. Out of the four options given, three are examples of continuous variation - height, weight, and skin colour. However, the correct answer is option C, which is tongue rolling. This is because tongue rolling is not a trait that shows a range of values. Instead, it is a trait that is either present or absent, meaning that it is a discrete variation. Discrete variation is the variation of traits that can only be grouped into certain categories, such as blood type or the ability to taste bitter substances. In contrast, continuous variation is the variation of traits that show a range of values, such as height or weight. To summarize, the answer to this Biology question is option C, tongue rolling, because it is not an example of continuous variation like the other options listed. Instead, it is an example of discrete variation.