Which of the following human traits in a class of school children may give an approximate normal distribution curve when the variation is plotted?

Heights of a class of school children may give an approximate normal distribution curve when the variation is plotted. This is because height is a continuous trait that is influenced by multiple genes and environmental factors, leading to a wide range of possible values. When plotted on a graph, the distribution of heights typically follows a bell-shaped curve with most individuals falling close to the average height and fewer individuals on either end of the spectrum (very tall or very short). This is known as a normal distribution curve, and it is commonly seen in traits that are influenced by many different factors, leading to a wide range of possible values. Blood groups, ear shapes, and sex distribution, on the other hand, are discrete traits with only a few possible values, and therefore would not typically follow a normal distribution curve when plotted.