What is discrete variation?

Discrete variation refers to traits that have distinct categories or limited possibilities, often resulting in a few distinct forms without any intermediate states. An example of this type of variation would be traits such as blood type or flower color in certain plants, where the traits can be classified into specific groups (e.g., type A, B, AB, O for blood types).

In contrast, traits influenced by multiple genes would reflect complex patterns of inheritance, sometimes leading to a continuous range of expression rather than distinct categories. Continuous changes denote traits that do not fit into clear-cut categories and instead display a range of variations, such as height in a population, where individuals can fall anywhere within a spectrum. Lastly, variations arising from environmental conditions emphasize how external factors can affect the expression of traits, rather than indicating discrete characteristics that are genetically determined. Thus, the defining characteristic of discrete variation is the presence of specific, limited trait options, making it the correct choice.