Final answer:
Non-Mendelian inheritance is the inheritance of traits that have a more complex genetic basis than one gene with two alleles and complete dominance. It includes factors such as incomplete dominance, codominance, multiple alleles, and environmental influences.
Step-by-step explanation:
Non-Mendelian inheritance refers to the inheritance of traits that have a more complex genetic basis than one gene with two alleles and complete dominance. In Mendelian genetics, traits are controlled by one gene with two alleles, resulting in just two possible phenotypes. However, many characteristics have more complex inheritance patterns, such as incomplete dominance, codominance, multiple alleles, and environmental influences.