Genetics is the study of how traits are inherited through genes and DNA, often with environmental influence. Everyday examples of genetic traits include freckles (strongly linked to the MC1R gene), red-green colorblindness (an X-linked single-gene trait), and PTC tasting (whether a bitter compound tastes strong or tasteless).
Other familiar traits—such as hair texture, dimples, and handedness—also have genetic components, but many are influenced by multiple genes and environment rather than a single simple dominant/recessive rule. Classroom genetics often uses these observable examples to illustrate inheritance patterns.
Source: University of Utah Genetic Science Learning Center — Observable Human Characteristics