Final answer:
True statements about non-Mendelian inheritance patterns include incomplete dominance, when heterozygous offspring show an intermediate phenotype; codominance, where both alleles are expressed equally; and polygenic inheritance, where multiple genes contribute to a trait.
Step-by-step explanation:
Regarding non-Mendelian inheritance patterns, the following statements are true: incomplete dominance, codominance, and polygenic inheritance. Unlike the simple dominant-recessive patterns described by Mendel, these non-Mendelian patterns involve more complex interactions between alleles. Incomplete dominance occurs when the phenotype of the heterozygotes is intermediate between those of the two homozygotes. An example of this would be if black and white true-breeding mice are mated and produce all gray offspring.
Codominance is when both alleles in the genotype are fully expressed in the phenotype. The ABO blood group is a classic example of codominance, where both A and B alleles are expressed in individuals with an AB blood type.
Lastly, polygenic inheritance involves multiple genes contributing to a single trait, such as skin color in humans, which is determined by the cumulative effect of multiple genes.